Pure JavaScript – Building A Real-World Application From Scratch

Pure JavaScript – Building A Real-World Application From Scratch

Modern JavaScript Frameworks like Angular, React and Vue.js makes it very easy to build complex single page web applications. However, using a those frameworks is not mandatory and you can also go with plain and pure JavaScript.

Modern JavaScript Frameworks like Angular, React and Vue.js makes it very easy to build complex single page web applications. However, using a those frameworks is not mandatory and you can also go with plain and pure JavaScript.

This tutorial guides you through building a web application in pure JavaScript step-by-step.

What We’re Going To Build

The application we’re going to build in this tutorial looks like the following:

This is a simple issue tracker application and as you can see the user interface is split up into two sections. On top an input form is visible. By using the input fields for Description, Severity and Assigned To the user is able to enter new issues. The issues are stored in the Browser’s Local Storage. The list of existing issues is printed out in the bottom area. Here you can see that each issue is printed out with the details of description, severity and assigned to. In addition you can see that the issue is identified by a unique issue id. The issue is a GUID which is generated when the issue is created and stored in the Local Storage as well.

Furthermore each issue has a status assigned. By default the status is “Open”. If an issue is resolved the user is able to set the status to “Closed” by using the Close button. The issue can be deleted from the list (and from Local Storage) by clicking on button Delete.

Setting Up The Project

The project setup is really simple. Because we only want to use pure JavaScript we do not need to install frameworks or dependencies. Start by creating a new project folder and inside that new folder create two empty new files: index.html and main.js.

The file index.html is the entry point for our application and contains the HTML code. The file main.js will be included in index.html is contains the corresponding JavaScript code which is needed to implement the sample application.

Creating index.html

We’re starting by creating a basic HTML structure in index.html as you can see in the following listing:

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>JS Issue Tracker</title>
  </head>
  <body>
    <script src="main.js"></script>
  </body>
</html>

including JQuery, Bootstrap and Chance.js

We’ll use Bootstrap CSS classes for applying styling to the user interface components. The easiest way to include Bootstrap is to add it from CDN.

First add the following in the head section:

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">


Then include the following in the body section (right before the closing </body> tag):

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>

We’re going to use a small JS library (ChanceJS) to generate unique identifiers for issues. Include that library by adding the following line as well:

<script src="https://chancejs.com/chance.min.js"></script>

Using live-server

As a development web server we’re using live-server in this tutorial. live-server is a small web server with reload capabilities. It’s available as an npm package, so installation can be done with:

$ npm install -g live-server

Having completed the installation the command live-server is available. If you execute this command in the project directory the web server starts and our application opens in the browser.

Implementating the UI

Let’s add the HTML code to index.html which is needed to implement the user interface:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- The above 3 meta tags *must* come first in the head; any other head content must come *after* these tags -->
    <title>JS Issue Tracker</title>

    <!-- Bootstrap -->
    <!-- Latest compiled and minified CSS -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">


  </head>
  <body onload="fetchIssues()">
    <div class="container">
      <h1>JS Issue Tracker <small>by CodingTheSmartWay.com</small></h1>
      <div class="jumbotron">
        <h3>Add New Issue:</h3>
        <form id="issueInputForm">
          <div class="form-group">
            <label for="issueDescInput">Description</label>
            <input type="text" class="form-control" id="issueDescInput" placeholder="Describe the issue ...">
          </div>
          <div class="form-group">
            <label for="issueDescInput">Severity</label>
             <select class="form-control" id="issueSeverityInput">
              <option value="Low">Low</option>
              <option value="Medium">Medium</option>
              <option value="High">High</option>
            </select> 
          </div>
          <div class="form-group">
            <label for="issueDescInput">Assigned To</label>
            <input type="text" class="form-control" id="issueAssignedToInput" placeholder="Enter responsible ...">
          </div>

          <button type="submit" class="btn btn-primary">Add</button>
        </form>
      </div>
      <div class="row">
        <div class="col-lg-12">
          <div id="issuesList">
          </div>
        </div>
      </div>
      <div class="footer">
        <p>&copy CodingTheSmartWay.com</p>
      </div>

    </div>
   

    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
    <script src="https://chancejs.com/chance.min.js"></script>

    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
    <script src="main.js"></script>
  </body>
</html>

First notice, that we’ve attached the onload fetchIssues() event handler to the <body>element. This makes sure that the JavaScript function fetchIssues() is called each time the application loads. fetchIssues() will be implemented later on in file main.js and will load all issues from Local Storage, generates the HTML output for the issues list and attaches the output to the DOM.

Within the body section one

element with the Bootstrap CSS class container is used to contain all other HTML elements.

Let’s take a look at the form implementation. It’s important to notice that all input elements and the <form> element itself get an id assigned. By using that identifier we can later on retrieve a reference to that element within the JavaScript code.

Furthermore it’s important to notice that the HTML code which is needed to output the list of existing issues is not included in index.html. The reason is obvious. The HTML which is needed for the list output is dynamic and depends on the issue records retrieved from Local Storage. So the only thing you can find here is a <div> element with id issuesList. This element gives us the possibility of generating the needed HTML code with JavaScript and then place the result within that element.

Fetching Issue Data From Local Storage

Let’s switch over to main.js and start implementing the JavaScript part of our application. The issue data should be saved in the Browser’s Local Storage. The first thing we’re going to implement is the code which is needed to retrieve issues from the Local Storage. We do that we adding function fetchIssues():

function fetchIssues () {
  var issues = JSON.parse(localStorage.getItem('issues'));
  var issuesList = document.getElementById('issuesList');
  
  issuesList.innerHTML = '';
  
  for (var i = 0; i < issues.length; i++) {
    var id = issues[i].id;
    var desc = issues[i].description;
    var severity = issues[i].severity;
    var assignedTo = issues[i].assignedTo;
    var status = issues[i].status;
    
    issuesList.innerHTML +=   '<div class="well">'+
                              '<h6>Issue ID: ' + id + '</h6>'+
                              '<p><span class="label label-info">' + status + '</span></p>'+
                              '<h3>' + desc + '</h3>'+
                              '<p><span class="glyphicon glyphicon-time"></span> ' + severity + ' '+
                              '<span class="glyphicon glyphicon-user"></span> ' + assignedTo + '</p>'+
                              '<a href="#" class="btn btn-warning" onclick="setStatusClosed(\''+id+'\')">Close</a> '+
                              '<a href="#" class="btn btn-danger" onclick="deleteIssue(\''+id+'\')">Delete</a>'+
                              '</div>';
  }
}

The first line of code is retrieving issues from Local Storage. This is done by executing localStorage.getItem('issues') and parse the string result into a JSON object.

With the second line of code we’re retrieving the reference to the <div> element with id issuesList. The HTML content of that element can be accessed by property innerHTML. First we’re using that property to set the content to an empty string. Next we’re looping over the elements in issues by using a for loop and adding the HTML output for that element to issuesList.innerHTML.

Saving Issue Data To Local Storage After Form Submit

First we need to attach an event handler to the submit event of the form. That is done by using the following line of code:

document.getElementById('issueInputForm').addEventListener('submit', saveIssue);


A reference to the form element is retrieved by using getElementById. We’re passing in the string issueInputForm which is the id of the <form> element. The addEventListener method is called to attach the submit event of the form to the saveIssue event handler function. Let’s implement this function next:

function saveIssue(e) {
  var issueId = chance.guid();
  var issueDesc = document.getElementById('issueDescInput').value;
  var issueSeverity = document.getElementById('issueSeverityInput').value;
  var issueAssignedTo = document.getElementById('issueAssignedToInput').value;
  var issueStatus = 'Open';

  var issue = {
    id: issueId,
    description: issueDesc,
    severity: issueSeverity,
    assignedTo: issueAssignedTo,
    status: issueStatus
  }
  
  if (localStorage.getItem('issues') === null) {
    var issues = [];
    issues.push(issue);
    localStorage.setItem('issues', JSON.stringify(issues));
  } else {
    var issues = JSON.parse(localStorage.getItem('issues'));
    issues.push(issue);
    localStorage.setItem('issues', JSON.stringify(issues));
  }
  
  document.getElementById('issueInputForm').reset();
 
  fetchIssues();
  
  e.preventDefault(); 
}

First, the input values from the form controls are retrieved and stored in local variables. The issueStatus is set to Open and issueId is generated by calling function chance.guid(). Next, the new issue object is inserted into the issues object in Local Storage.

Having inserted the issues object into Local Storage we need to empty the form by calling the reset() method. We’re calling fetchIssues() again to make sure that the list output is re-generated and that the new issue item will be visible.

Finally, we need to execute e.preventDefault() to avoid that the default submission of the form is taking place.

Setting The Closed Status

The HTML output which is generated for each issue item in function fetchIssues contains a button which can be used to set the issue status to Closed:

<a href="#" class="btn btn-warning" onclick="setStatusClosed(\''+id+'\')">Close</a>


Here we’re attaching the click event to the event handler method setStatusClosed. The implementation of this method is available in the following listing:

function setStatusClosed (id) {
  var issues = JSON.parse(localStorage.getItem('issues'));
  
  for(var i = 0; i < issues.length; i++) {
    if (issues[i].id == id) {
      issues[i].status = "Closed";
    }
  }
    
  localStorage.setItem('issues', JSON.stringify(issues));
  
  fetchIssues();
}

The id of the current issue item is passed in as a parameter. To retrieve the corresponding item from Local Storage we first need to retrieve the issue items in JSON format. This is done by calling localStorage.getItem('issues') and passing the result to the JSON.parse()method.

Deleting An Issue

Another button is generated for each issue item:

<a href="#" class="btn btn-danger" onclick="deleteIssue(\''+id+'\')">Delete</a>


By clicking on this button the user should be able to delete the current issue item from the list and from Local Storage. The click event is bound to the deleteIssue event handler function. The implementation of this method can be seen in the following:

function deleteIssue (id) {
  var issues = JSON.parse(localStorage.getItem('issues'));
  
  for(var i = 0; i < issues.length; i++) {
    if (issues[i].id == id) {
      issues.splice(i, 1);
    }
  }
  
  localStorage.setItem('issues', JSON.stringify(issues));
  
  fetchIssues();
}

The implementation is similar to the implementation of the setStatusClosed function we saw before. The main difference is that we’re using the splice method to delete the current item from the array issues. After having removed the current issue item from the array we’re writing it back to Local Storage and execute function fetchIssues again to update the list output.

Summary

Modern JavaScript frameworks like Angular, React and Vue.js makes it easy and convenient to write single page web application. However those frameworks are not essential and you can achieve the same results with plain & pure JavaScript. Furthermore, understanding the basics of JavaScript will help you to learn and use JS frameworks.

In this tutorial you’ve learned the basics of JavaScript by following a practical example, the issue tracker demo.

JavaScript Tutorial: if-else Statement in JavaScript

JavaScript Tutorial: if-else Statement in JavaScript

This JavaScript tutorial is a step by step guide on JavaScript If Else Statements. Learn how to use If Else in javascript and also JavaScript If Else Statements. if-else Statement in JavaScript. JavaScript's conditional statements: if; if-else; nested-if; if-else-if. These statements allow you to control the flow of your program's execution based upon conditions known only during run time.

Decision Making in programming is similar to decision making in real life. In programming also we face some situations where we want a certain block of code to be executed when some condition is fulfilled.
A programming language uses control statements to control the flow of execution of the program based on certain conditions. These are used to cause the flow of execution to advance and branch based on changes to the state of a program.

JavaScript’s conditional statements:

  • if
  • if-else
  • nested-if
  • if-else-if

These statements allow you to control the flow of your program’s execution based upon conditions known only during run time.

  • if: if statement is the most simple decision making statement. It is used to decide whether a certain statement or block of statements will be executed or not i.e if a certain condition is true then a block of statement is executed otherwise not.
    Syntax:
if(condition) 
{
   // Statements to execute if
   // condition is true
}

Here, condition after evaluation will be either true or false. if statement accepts boolean values – if the value is true then it will execute the block of statements under it.
If we do not provide the curly braces ‘{‘ and ‘}’ after if( condition ) then by default if statement will consider the immediate one statement to be inside its block. For example,

if(condition)
   statement1;
   statement2;

// Here if the condition is true, if block 
// will consider only statement1 to be inside 
// its block.

Flow chart:

Example:

<script type = "text/javaScript"> 

// JavaScript program to illustrate If statement 

var i = 10; 

if (i > 15) 
document.write("10 is less than 15"); 

// This statement will be executed 
// as if considers one statement by default 
document.write("I am Not in if"); 

< /script> 

Output:

I am Not in if
  • if-else: The if statement alone tells us that if a condition is true it will execute a block of statements and if the condition is false it won’t. But what if we want to do something else if the condition is false. Here comes the else statement. We can use the else statement with if statement to execute a block of code when the condition is false.
    Syntax:
if (condition)
{
    // Executes this block if
    // condition is true
}
else
{
    // Executes this block if
    // condition is false
}


Example:

<script type = "text/javaScript"> 

// JavaScript program to illustrate If-else statement 

var i = 10; 

if (i < 15) 
document.write("10 is less than 15"); 
else
document.write("I am Not in if"); 

< /script> 

Output:

i is smaller than 15
  • nested-if A nested if is an if statement that is the target of another if or else. Nested if statements means an if statement inside an if statement. Yes, JavaScript allows us to nest if statements within if statements. i.e, we can place an if statement inside another if statement.
    Syntax:
if (condition1) 
{
   // Executes when condition1 is true
   if (condition2) 
   {
      // Executes when condition2 is true
   }
}

Example:

<script type = "text/javaScript"> 

// JavaScript program to illustrate nested-if statement 

var i = 10; 

if (i == 10) { 

// First if statement 
if (i < 15) 
	document.write("i is smaller than 15"); 

// Nested - if statement 
// Will only be executed if statement above 
// it is true 
if (i < 12) 
	document.write("i is smaller than 12 too"); 
else
	document.write("i is greater than 15"); 
} 
< /script> 

Output:

i is smaller than 15
i is smaller than 12 too
  • if-else-if ladder Here, a user can decide among multiple options.The if statements are executed from the top down. As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the ladder is bypassed. If none of the conditions is true, then the final else statement will be executed.
if (condition)
    statement;
else if (condition)
    statement;
.
.
else
    statement;


Example:

<script type = "text/javaScript"> 
// JavaScript program to illustrate nested-if statement 

var i = 20; 

if (i == 10) 
document.wrte("i is 10"); 
else if (i == 15) 
document.wrte("i is 15"); 
else if (i == 20) 
document.wrte("i is 20"); 
else
document.wrte("i is not present"); 
< /script> 

Output:

i is 20

How to Retrieve full Profile of LinkedIn User using Javascript

How to Retrieve full Profile of LinkedIn User using Javascript

I am trying to retrieve the full profile (especially job history and educational qualifications) of a linkedin user via the Javascript (Fetch LinkedIn Data Using JavaScript)

Here we are fetching LinkedIn data like Username, Email and other fields using JavaScript SDK.

Here we have 2 workarounds.

  1. Configuration of linkedIn developer api
  2. Javascript Code to fetch records

Configuration of linkedIn developer api

In order to fetch records, first we need to create developer api in linkedin which will act as token/identity while fetching data from other linkedin accounts.

So to create api, navigate to https://linkedin.com/developer/apps and click on 'Create Application'.

After navigating, fill in details like name, description and other required fields and then submit.

As we submit, it will create Client ID and Client Secret shown below, which we will be using in our code while communicating to fetch records from other LinkedIn account.

Note: We need to provide localhost Url here under Oauth 2.0. I am using my localhost, but you can probably use other production URLs under Oauth 2.0 where your app is configured. It will make your api  consider the Url as trusted which fetching records.

Javascript Code to fetch records

For getting user details like first name, last name,User image can be written as,

<script type="text/javascript" src="https://platform.linkedin.com/in.js">  
    api_key: XXXXXXX //Client ID  
    onLoad: OnLinkedInFrameworkLoad //Method that will be called on page load  
    authorize: true  
</script>  
<script type="text/javascript">  
    function OnLinkedInFrameworkLoad() {  
        IN.Event.on(IN, "auth", OnLinkedInAuth);  
    }  
  
    function OnLinkedInAuth() {  
        IN.API.Profile("me").result(ShowProfileData);  
    }  
  
    function ShowProfileData(profiles) {  
        var member = profiles.values[0];  
        var id = member.id;  
        var firstName = member.firstName;  
        var lastName = member.lastName;  
        var photo = member.pictureUrl;  
        var headline = member.headline;  
        //use information captured above  
        var stringToBind = "<p>First Name: " + firstName + " <p/><p> Last Name: " + lastName + "<p/><p>User ID: " + id + " and Head Line Provided: " + headline + "<p/>"  
        document.getElementById('profiles').innerHTML = stringToBind;  
    }  
</script>    

Kindly note we need to include 'https://platform.linkedin.com/in.js' as src under script type as it will act on this Javascript SDK provided by Linkedin.

In the same way we can also fetch records of any organization with the companyid as keyword.

<head>  
    <script type="text/javascript" src="https://platform.linkedin.com/in.js">  
        api_key: XXXXXXX ////Client ID  
        onLoad: onLinkedInLoad  
        authorize: true  
    </script>  
</head>  
  
<body>  
    <div id="displayUpdates"></div>  
    <script type="text/javascript">  
        function onLinkedInLoad() {  
            IN.Event.on(IN, "auth", onLinkedInAuth);  
            console.log("On auth");  
        }  
  
        function onLinkedInAuth() {  
            var cpnyID = XXXXX; //the Company ID for which we want updates  
            IN.API.Raw("/companies/" + cpnyID + "/updates?event-type=status-update&start=0&count=10&format=json").result(displayCompanyUpdates);  
            console.log("After auth");  
        }  
  
        function displayCompanyUpdates(result) {  
            var div = document.getElementById("displayUpdates");  
            var el = "<ul>";  
            var resValues = result.values;  
            for (var i in resValues) {  
                var share = resValues[i].updateContent.companyStatusUpdate.share;  
                var isContent = share.content;  
                var isTitled = isContent,  
                    isLinked = isContent,  
                    isDescription = isContent,  
                    isThumbnail = isContent,  
                    isComment = isContent;  
                if (isTitled) {  
                    var title = isContent.title;  
                } else {  
                    var title = "News headline";  
                }  
                var comment = share.comment;  
                if (isLinked) {  
                    var link = isContent.shortenedUrl;  
                } else {  
                    var link = "#";  
                }  
                if (isDescription) {  
                    var description = isContent.description;  
                } else {  
                    var description = "No description";  
                }  
                /* 
                if (isThumbnailz) { 
                var thumbnailUrl = isContent.thumbnailUrl; 
                } else { 
                var thumbnailUrl = "http://placehold.it/60x60"; 
                } 
                */  
                if (share) {  
                    var content = "<a target='_blank' href=" + link + ">" + comment + "</a><br>";  
                    //el += "<li><img src='" + thumbnailUrl + "' alt=''>" + content + "</li>";  
                    el += "<li><div>" + content + "</div></li>";  
                }  
                console.log(share);  
            }  
            el += "</ul>";  
            document.getElementById("displayUpdates").innerHTML = el;  
        }  
    </script>  
</body>  

We can get multiple metadata while fetching records for any any organization. We can get company updates as shown below.

Conclusion

We can also fetch any company specific data like company job updates/post, total likes, comments, and number of views along with a lot of metadata we can fetch which I have shown below.

Thank you for reading !

7 Best Javascript Iframe Libraries

7 Best Javascript Iframe Libraries

Iframes let you build user experiences into embeddable ‘cross-domain components’, which let users interact with other sites without being redirected. I have compiled 7 best Javascript iframe libraries.

Iframes let you build user experiences into embeddable ‘cross-domain components’, which let users interact with other sites without being redirected. I have compiled 7 best Javascript iframe libraries.

1. Zoid

A cross-domain component toolkit, supporting:

  • Render an iframe or popup on a different domain, and pass down props, including objects and functions
  • Call callbacks natively from the child window without worrying about post-messaging or cross-domain restrictions
  • Create and expose components to share functionality from your site to others!
  • Render your component directly as a React, Vue or Angular component!
    It's 'data-down, actions up' style components, but 100% cross-domain using iframes and popups!

Download


2. Postmate

Postmate is a promise-based API built on postMessage. It allows a parent page to speak with a child iFrame across origins with minimal effort.

Download


3. Iframe Resizer

Keep same and cross domain iFrames sized to their content with support for window/content resizing, in page links, nesting and multiple iFrames

Demo

Download


4. Iframely

Embed proxy. Supports over 1800 domains via custom parsers, oEmbed, Twitter Cards and Open Graph

Demo

Download


5. React Frame component

This component allows you to encapsulate your entire React application or per component in an iFrame.

Demo

Download


6. Seamless.js

A seamless iframe makes it so that visitors are unable to distinguish between content within the iframe and content beside the iframe. Seamless.js is a JavaScript library (with no dependencies) that makes working with iframes easy by doing all the seamless stuff for you automatically.

Demo

Download


7. Porthole

A proxy to safely communicate to cross-domain iframes in javascript

Demo

Download


Thank for read!