Create a Custom PDF Viewer With JavaScript

Create a Custom PDF Viewer With JavaScript

Create a Custom PDF Viewer With JavaScript: In this practical project we will use pdf.js to create a custom pdf view interface with pagination using JavaScript. We will be using modern syntax such as arrow functions and promises.

In this practical project we will use pdf.js to create a custom pdf view interface with pagination using JavaScript. We will be using modern syntax such as arrow functions and promises.

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

Build a Full Custom PDF Viewer App in JavaScript Using PDF.js Library

Build a Full Custom PDF Viewer App in JavaScript Using PDF.js Library

PDF.js is an open-source JavaScript library that allows you to parse and render PDF files right inside your web pages. In this tutorial, I'll show you how to use it to build a full custom PDF Viewer App in Javascript using PDF.js Library. How to create a fully fledged custom JavaScript PDF viewer from scratch.

PDF.js is an open-source JavaScript library that allows you to parse and render PDF files right inside your web pages. In this tutorial, I'll show you how to use it to build a full custom PDF Viewer App in Javascript using PDF.js Library. How to create a fully fledged custom JavaScript PDF viewer from scratch.

How To Convert HTML To PDF using JavaScript

How To Convert HTML To PDF using JavaScript

In this tutorial, we will show you how to generate PDF file of your HTML page with CSS using JavaScript and jQuery. We have to add two external JS files for converting the PDF -  JSPDF.js and html2canvas.js.

In this blog, I will demonstrate how to generate PDF file of your HTML page with CSS using JavaScript and jQuery. We have to add two external JS files for converting the PDF -  JSPDF.js and html2canvas.js.

Creating an HTML Page for converting the HTMl to PDF

Add the following table in your HTML page.

<form class="form" style="max-width: none; width: 1005px;">  
  
  
        <h2 style="color: #0094ff">Hello</h2>  
        <h3>a bit about this Project:</h3>  
        <p style="font-size: large">  
            I will demonstrate how to generate PDF file of your HTML page with CSS using JavaScript and J query.  
        </p>  
        <table>  
            <tbody>  
                <tr>  
                    <th>Company</th>  
                    <th>Contact</th>  
                    <th>Country</th>  
                </tr>  
                <tr>  
                    <td>Alfreds Futterkiste</td>  
                    <td>Maria Anders</td>  
                    <td>Germany</td>  
                </tr>  
                <tr>  
                    <td>Centro comercial Moctezuma</td>  
                    <td>Francisco Chang</td>  
                    <td>Mexico</td>  
                </tr>  
                <tr>  
                    <td>Ernst Handel</td>  
                    <td>Roland Mendel</td>  
                    <td>Austria</td>  
                </tr>  
                <tr>  
                    <td>Island Trading</td>  
                    <td>Helen Bennett</td>  
                    <td>UK</td>  
                </tr>  
                <tr>  
                    <td>Laughing Bacchus Winecellars</td>  
                    <td>Yoshi Tannamuri</td>  
                    <td>Canada</td>  
                </tr>  
                <tr>  
                    <td>Magazzini Alimentari Riuniti</td>  
                    <td>Giovanni Rovelli</td>  
                    <td>Italy</td>  
                </tr>  
            </tbody>  
        </table>  
  
  
    </form>  

Add the style of this HTML page.

<style>  
        table {  
            font-family: arial, sans-serif;  
            border-collapse: collapse;  
            width: 100%;  
        }  
  
        td, th {  
            border: 1px solid #dddddd;  
            text-align: left;  
            padding: 8px;  
        }  
  
        tr:nth-child(even) {  
            background-color: #dddddd;  
        }  
    </style>  

Add the "Print" button in this page, above the form tag.

<input type="button" id="create_pdf" value="Generate PDF">  

Add the following script in HTML page for converting it to pdf.

<script src="https://code.jquery.com/jquery-1.12.4.min.js" integrity="sha256-ZosEbRLbNQzLpnKIkEdrPv7lOy9C27hHQ+Xp8a4MxAQ=" crossorigin="anonymous"></script>  
   <script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.3.5/jspdf.min.js"></script>  

Add other two scripts for converting the document.

<script>  
    (function () {  
        var  
         form = $('.form'),  
         cache_width = form.width(),  
         a4 = [595.28, 841.89]; // for a4 size paper width and height  
  
        $('#create_pdf').on('click', function () {  
            $('body').scrollTop(0);  
            createPDF();  
        });  
        //create pdf  
        function createPDF() {  
            getCanvas().then(function (canvas) {  
                var  
                 img = canvas.toDataURL("image/png"),  
                 doc = new jsPDF({  
                     unit: 'px',  
                     format: 'a4'  
                 });  
                doc.addImage(img, 'JPEG', 20, 20);  
                doc.save('Bhavdip-html-to-pdf.pdf');  
                form.width(cache_width);  
            });  
        }  
  
        // create canvas object  
        function getCanvas() {  
            form.width((a4[0] * 1.33333) - 80).css('max-width', 'none');  
            return html2canvas(form, {  
                imageTimeout: 2000,  
                removeContainer: true  
            });  
        }  
  
    }());  
</script>  
<script>  
    /* 
 * jQuery helper plugin for examples and tests 
 */  
    (function ($) {  
        $.fn.html2canvas = function (options) {  
            var date = new Date(),  
            $message = null,  
            timeoutTimer = false,  
            timer = date.getTime();  
            html2canvas.logging = options && options.logging;  
            html2canvas.Preload(this[0], $.extend({  
                complete: function (images) {  
                    var queue = html2canvas.Parse(this[0], images, options),  
                    $canvas = $(html2canvas.Renderer(queue, options)),  
                    finishTime = new Date();  
  
                    $canvas.css({ position: 'absolute', left: 0, top: 0 }).appendTo(document.body);  
                    $canvas.siblings().toggle();  
  
                    $(window).click(function () {  
                        if (!$canvas.is(':visible')) {  
                            $canvas.toggle().siblings().toggle();  
                            throwMessage("Canvas Render visible");  
                        } else {  
                            $canvas.siblings().toggle();  
                            $canvas.toggle();  
                            throwMessage("Canvas Render hidden");  
                        }  
                    });  
                    throwMessage('Screenshot created in ' + ((finishTime.getTime() - timer) / 1000) + " seconds<br />", 4000);  
                }  
            }, options));  
  
            function throwMessage(msg, duration) {  
                window.clearTimeout(timeoutTimer);  
                timeoutTimer = window.setTimeout(function () {  
                    $message.fadeOut(function () {  
                        $message.remove();  
                    });  
                }, duration || 2000);  
                if ($message)  
                    $message.remove();  
                $message = $('<div ></div>').html(msg).css({  
                    margin: 0,  
                    padding: 10,  
                    background: "#000",  
                    opacity: 0.7,  
                    position: "fixed",  
                    top: 10,  
                    right: 10,  
                    fontFamily: 'Tahoma',  
                    color: '#fff',  
                    fontSize: 12,  
                    borderRadius: 12,  
                    width: 'auto',  
                    height: 'auto',  
                    textAlign: 'center',  
                    textDecoration: 'none'  
                }).hide().fadeIn().appendTo('body');  
            }  
        };  
    })(jQuery);  
  
</script>  

Now, let's see the output.

Click on the "Generate PDF " button and get the PDF file like this.

Conclusion

You can easily add the Export to PDF functionality in the web page without depending on the server-side script. The PDF creation functionality can be enhanced with jsPDF configuration options as per your needs. Thank you for reading !