Code：loadScript()加载js的功能函数_javascript技巧

function loadScript (url, callback) {
var script = document.createElement('script');
script.type = 'text/javascript';
/* should be application/javascript
* http://www.rfc-editor.org/rfc/rfc4329.txt
* http://connect.microsoft.com/IE/feedback/ViewFeedback.aspx?FeedbackID=84613
*/
if (callback)
script.onload = script.onreadystatechange = function() {
if (script.readyState && script.readyState != 'loaded' && script.readyState != 'complete')
return;
script.onreadystatechange = script.onload = null;
callback();
};
script.src = url;
document.getElementsByTagName('head')[0].appendChild (script);
}

实例：
代码如下:
// prevent google analytics from slowing down page loading
window.addEventListener ('load', function() {
loadScript ('http://www.google-analytics.com/urchin.js', function() {
window._uacct = 'UA-xxxxxx-x';
urchinTracker();
});
}, false);