Import JavaScript file in JavaScript function [duplicate]

Question

Possible Duplicates:Include a JavaScript file in a JavaScript fileHow to include a JavaScript file in another JavaScript file?

What is the best way to import a JavaScript file, for example file.js, in a JavaScript function()?

For example, what is the best way to replace the todo statement:

function doSomething() { if (xy.doSomething == undefined) { // TODO: load 'oldVersionPatch.js' } ... } 

Possibly the best solution is to create script element and add it into the HTML page.

• Is it better to add/append it into head, or body (what will load when)?
• Is it better to use JavaScript or jQuery (what is more cross-browser compatible)?

Answer 1

http://api.jquery.com/jQuery.getScript/

or

(function(){ this.__defineGetter__("__FILE__", function() { return (new Error).stack.split("\n")[2].split("@")[1].split(":").slice(0,-1).join(":"); }); })(); (function(){ this.__defineGetter__("__DIR__", function() { return __FILE__.substring(0, __FILE__.lastIndexOf('/')); }); })(); function include(file,charset) { if (document.createElement && document.getElementsByTagName) { var head = document.getElementsByTagName('head')[0]; var script = document.createElement('script'); script.setAttribute('type', 'text/javascript'); script.setAttribute('src', __DIR__ + '/' + file); if(charset){ script.setAttribute('charset', charset); } head.appendChild(script); } } 

Answer 2

 var filename = 'oldVersionPatch.js'; var js = document.createElement('script'); js.setAttribute("type","text/javascript"); js.setAttribute("src", filename); document.getElementsByTagName("head")[0].appendChild(js); 

.. should do it

Answer 3

Very simply, in JavaScript create a <script> element, append the src attribute with whatever the URL is and attach to the DOM. That should do it.

Answer 4

You have to make your code asynchronous to gain this:

var script = document.createElement('script'); script.type = 'text/javascript'; script.src = yourJavascriptFileLocation; script.onload = script.onreadystatechange = function() { if (!script.readyState || script.readyState === 'complete') { /* Your code rely on this JavaScript code */ } }; var head = document.getElementsByTagName('head')[0]; // Don't use appendChild head.insertBefore(script, head.firstChild);