Load external JS from bookmarklet?

How can I load an external JavaScript file using a bookmarklet? This would overcome the URL length limitations of IE and generally keep things cleaner.

2015 Update

Content security policy will prevent this from working in many sites now. For example, the code below won't work on Facebook.

2008 answer

Use a bookmarklet that creates a script tag which includes your external JS.

As a sample:

javascript:(function(){document.body.appendChild(document.createElement('script')).src='** your external file URL here **';})();

Firefox and perhaps others support multiline bookmarklets, no need for one liner. When you paste in the code it just replaces newlines with spaces.

javascript:
var q = document.createElement('script');
q.src = 'http://svnpenn.github.io/bm/yt.js';
document.body.appendChild(q);
void 0;

Example

If I can add method tested in FF & Chrome (for readibility split to multiple lines):

javascript:var r = new XMLHttpRequest();
           r.open("GET", "https://...my.js", true);
           r.onloadend = function (oEvent) {
               new Function(r.responseText)();
               /* now you can use your code */
           };
           r.send();
           undefined

I always prefer to use a popular open source project loadjs

it is cross browser tested and has more functionality/comfort features.

So the code will look like this:

loadjs=function(){function e(e,n){var t,r,i,c=[],o=(e=e.push?e:[e]).length,f=o;for(t=function(e,t){t.length&&c.push(e),--f||n(c)};o--;)r=e[o],(i=s[r])?t(r,i):(u[r]=u[r]||[]).push(t)}function n(e,n){if(e){var t=u[e];if(s[e]=n,t)for(;t.length;)t[0](e,n),t.splice(0,1)}}function t(e,n,r,i){var o,s,u=document,f=r.async,a=(r.numRetries||0)+1,h=r.before||c;i=i||0,/(^css!|\.css$)/.test(e)?(o=!0,(s=u.createElement("link")).rel="stylesheet",s.href=e.replace(/^css!/,"")):((s=u.createElement("script")).src=e,s.async=void 0===f||f),s.onload=s.onerror=s.onbeforeload=function(c){var u=c.type[0];if(o&&"hideFocus"in s)try{s.sheet.cssText.length||(u="e")}catch(e){u="e"}if("e"==u&&(i+=1)<a)return t(e,n,r,i);n(e,u,c.defaultPrevented)},!1!==h(e,s)&&u.head.appendChild(s)}function r(e,n,r){var i,c,o=(e=e.push?e:[e]).length,s=o,u=[];for(i=function(e,t,r){if("e"==t&&u.push(e),"b"==t){if(!r)return;u.push(e)}--o||n(u)},c=0;c<s;c++)t(e[c],i,r)}function i(e,t,i){var s,u;if(t&&t.trim&&(s=t),u=(s?i:t)||{},s){if(s in o)throw"LoadJS";o[s]=!0}r(e,function(e){e.length?(u.error||c)(e):(u.success||c)(),n(s,e)},u)}var c=function(){},o={},s={},u={};return i.ready=function(n,t){return e(n,function(e){e.length?(t.error||c)(e):(t.success||c)()}),i},i.done=function(e){n(e,[])},i.reset=function(){o={},s={},u={}},i.isDefined=function(e){return e in o},i}();
loadjs('//path/external/js', {
    success: function () {
        console.log('something to run after the script was loaded');
    });