Pdf viewer in Javascript

index.html

<canvas id="pdf_canvas"></canvas>
<div class="container">
        <button id="prev_page">Previos Page</button>
        <button id="next_page">next Page</button>
        <span id="current_page_num"></span>
            of
        <span id="total_page_num"></span>

        <input type="text" id="page_num">
        <button id="go_to_page">Go To Page</button>
</div>

<!-- Replace pdf.js with downloaded pdf.js file location-->
<script src="pdf.js" charset="utf-8"></script> 
<script src="script.js" charset="utf-8"></script>