4 JavaScript Challenges, 13 high-school students, 2 hours

4 JavaScript Challenges, 13 high-school students, 2 hours

<strong>Originally published by </strong><a href="https://dev.to/carlillo" target="_blank">Carlos Caballero</a> <em>at&nbsp;</em><a href="https://dev.to/carlillo/4-javascript-challenges-13-high-school-students-2-hours-4456" target="_blank">dev.to</a>

This week the cultural week was celebrated in the high school where I work teaching students of Web application development.

A co-worker who teaches programming for pre-grade students (a brief introduction to computer science) let me know that there was a group of 13 students who wanted to study the Computer Science Degree the following year, so I came up with the idea to teach with them a programming workshop with my students.

The first thing I requested is that the workshop only be attended by students who wished to learn programming. In addition, I had a first contact with them before the workshop, during which we talked about their previous knowledge and their personal interest in the workshop. The students knew the following concepts in C:

  • Variables and constants.
  • Control structures: if, else-if, while, for, do-while.
  • Functions.

They had no knowledge in the use of data structures such as arrays.

Furthermore, I spoke with my students to prepare a workshop that would be somewhat different from the traditional ones, where there is a single speaker and several assistants. Therefore, our methodology would be the following:

  • We match a high school student with a vocational training student.
  • We show the final result of the challenge and we indicate a small clue as to how the problem should be solved.
  • The high school students would begin to work together with their partner who neither give them the solution, nor touch the keyboard. The partner’s goal would be to explain the concepts and above all help them with syntax issues.
  • Each couple would go at their own pace. When each couple finished an exercise, they should let me know so that I would have a record of the group’s pace.
  • At the end of the first hour, the high school students would present their solutions on the whiteboard so that their classmates could see the final result.

The next thing we did was to plan the challenges, bearing in mind that the high school had a space of 2 hours to solve them. For this, each one of the vocational training students prepared a small challenge, together with the solution.

When all the students had prepared their challenges we had to decide which ones were going to be used. To make this decision, we spent 1 hour looking at the possible challenges and categorizing them by difficulty. We removed several parts of the code, which the high school students would complete the day of the workshop.

Once this part was completed, we prepared a Git repository so that all the vocational training students would have the same information (challenges and solutions).

Breaking the ice

The day of the workshop there were 26 young people with ages ranging between 17 and 23 divided in two groups. Therefore, what we had to do was divide them in pairs and break the ice between them.

So, although it is not normal at these ages in a Spanish high school, we played a small game:

  • They formed two rows, where each group would stand face-to-face.
  • I told them that they had to learn the name, age and hobby of the person in front of them. Besides, they had to pay attention to the details of the clothes.
  • Every 15 seconds, the students in one of the rows shifted to their left, so the person in front of them changed. Then, they repeated the questions.

In this way in a few minutes, everyone had introduced themselves. In addition, they had all their attention focused on learning the name, age and hobby of the the person they had in front.

At the end of the exercise, I placed the rows as before the game and asked them one by one if they were capable of remembering the name of the person on the left of the one standing in front of them (not the one in front of them, that would have been too easy). Very few of them were able to remember the name.

What did we learn from this exercise?

  • The human being can not remember many variables (some studies indicate that 7 is the average number).
  • We had just made an algorithm, in fact, it was a control structure: Loops.
  • Everyone had relaxed, and the ice had definitely been broken, we no longer had two groups of strangers, they had already played a game together and been introduced.

Now we are going to describe the challenges that we proposed for the workshop.

Problem 1 — Calculator

The first challenge is quite simple, since it was used for the students to learn the basic JavaScript variable definition syntax.

This challenge consisted of a form with two input values (number 1 and number 2) and a button that, when pressed, showed the results of all the following operations: addition, subtraction, multiplication, division, rest, the double value of the first number and, finally, double the second number.

The HTML document in this problem is the one shown below:

The JavaScript file provided to the students is the following, in which there are comments with the text TODO where they should make modifications.

Problem 2 — Guess a number

The second problem is slightly more complex. The goal is to create an algorithm in which a number between 1 and 7 is randomly generated. The player can then enter numbers to try and guess it. There are 3 attempts to guess the number, if not, the game is lost. In either case a message must be shown to the player.

The HTML document in this problem is the one shown below:

The JavaScript file provided to the students is the following one:

Problem 3 — Rope Game

The third problem incorporates visual elements to attract the attention of the high school students. In this case we will implement the logic to play Rope-Game. This game will consist of two keystrokes that will move the rope in one direction or another. The player who moves the rope past a limit will win the game.

In this problem the high school students must implement the logic of the conditions of the movement of the rope, as well as the logic to determine when a player has won the game.

In addition, the code is written in such a way that they can perfectly understand how to take control of a key pressed in the web browser.

The JavaScript file provided to the students is the following one:

Problem 4 — Soccer Game

The last problem is much more complex and fun than the previous ones. In this case, we will have a soccer field and a ball which we can move using any of the 4 cursor keys.

The high school students must implement the shooting function (the movement is already programmed since it is very similar to the code created in the previous challenge). In addition, they must determine the field boundaries to restore the ball to the center of the field.

The JavaScript file provided to the students is the following one:

At the end of the workshop, we took a small sample of the students’ experiences about the workshop and this is the summary:

El taller me ha parecido una gran idea para poder meternos en el mundo de la informática y conocer a gente del campo. ¡Las personas que lo han preparado son geniales y las actividades muy divertidas! Espero más talleres así de interactivos. ( The workshop seemed like a great idea to be able to get into the world of computing and meet people from the field. The people who have prepared it are great and the activities very fun! I look forward to more interactive workshops.)> Este taller ha estado muy interesante. Además es útil para ver otros lenguajes de programación y conocer gente y sus distintos puntos de vista y forma de solucionar problemas. ( This workshop has been very interesting. It is also useful to see other programming languages and meet people and their different points of view and ways to solve problems.)> Me ha parecido un taller muy interesante. Nos han enseñado cosas que no habíamos visto antes y han tenido mucha paciencia para guiarnos en nuestras dudas. En resumen, genial. ( I found the workshop to be very interesting. They have taught us things we had not seen before and have had a lot of patience to guide us in our doubts. In short, great.)> El taller ha sido genial, he aprendido bastante y Juan me ha caído súper bien. ( The workshop has been great, I’ve learned a lot and I really liked Juan.)
My personal experience as Vocational Training and University teacher has been very pleasant. Students are usually motivated with what they study and have a passion for Computer Science (CS). In fact, these students demonstrated during the 2 hours of the workshop that they were largely motivated to solve the problems.

The ice-breaking exercise was a success. During the two hours, my students have been teaching both fundamental JavaScript concepts and logical thinking to the high school students, without even stopping for a break.

Therefore, peer learning is more positive than the classic method of having a main speaker and several assistants.

The problems have been solved by vocational training students and can be found in the public repository.

In conclusion, this workshop can be used for students who have basic notions of programming and want to introduce themselves to creating code using a programming language such as JavaScript.

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!