Ways to add javascript files dynamically in a page

Question

I have seen Scriptaculous.js file to include its required javascript files dynamically. Is there any better approach to include javascript dynamically.

For example,

Answer 1

Create a script tag, set the URL, add it to the document:

let script = document.createElement("script");
script.src = "https://example.com/your_script.js"; 
document.body.appendChild(script);

That's it. There are too many overly complicated answers on this page for such a simple task.

If you're using modern JavaScript, you can use dynamic importing with a syntax like await import(...). That's out of the scope of this answer, but you can read more about that here.

Answer 2

To load a .js or .css file dynamically, in a nutshell, it means using DOM methods to first create a swanky new "SCRIPT" or "LINK" element, assign it the appropriate attributes, and finally, use element.appendChild() to add the element to the desired location within the document tree. It sounds a lot more fancy than it really is. Lets see how it all comes together:

function loadjscssfile(filename, filetype){
 if (filetype=="js"){ //if filename is a external JavaScript file
  var fileref=document.createElement('script')
  fileref.setAttribute("type","text/javascript")
  fileref.setAttribute("src", filename)
 }
 else if (filetype=="css"){ //if filename is an external CSS file
  var fileref=document.createElement("link")
  fileref.setAttribute("rel", "stylesheet")
  fileref.setAttribute("type", "text/css")
  fileref.setAttribute("href", filename)
 }
 if (typeof fileref!="undefined")
  document.getElementsByTagName("head")[0].appendChild(fileref)
}

loadjscssfile("myscript.js", "js") //dynamically load and add this .js file
loadjscssfile("javascript.php", "js") //dynamically load "javascript.php" as a JavaScript file
loadjscssfile("mystyle.css", "css") ////dynamically load and add this .css file

i hope its use full

Answer 3

To add a new javascript file dynamically:

function includeJS(jsFile) {
    $('head').append($('<script>').attr('type', 'text/javascript').attr('src', jsFile));
}


// Pick a JS to load
if ($.browser.msie) {
    includeJS('first.js');
} else {
    includeJS('second.js');
}
includeJS('third.js');