I need to execute a javascript before the page is start to load? how can i do it? Atfirst my script should execute, after pletion of script, if i need i should load the page else i shouln't load it. For example if my script redirect to another page i shouldnot load the current page else i should load it.

I need to execute a javascript before the page is start to load? how can i do it? Atfirst my script should execute, after pletion of script, if i need i should load the page else i shouln't load it. For example if my script redirect to another page i shouldnot load the current page else i should load it.

• javascript
• jquery
• extjs

• From your ments below, I'm guessing that the script is executing first, but the rest of the page has a second to load while the new HTTP request is waiting for a response. Perhaps you could try wrapping the content of the page in <noscript> tags. – user113716 Commented Oct 18, 2010 at 13:49
• This is a bad idea if it is for security. All of the content is sent down to the puter and anyone watching the traffic or with JS disabled can get the content. – epascarello Commented Oct 18, 2010 at 13:53
• @epascarello - Yeah, we don't know what the ultimate intention is. I was thinking it was perhaps a simple redirect to a javascript enhanced page. You're right that it is not a solution if security is in mind. But then any javascript solution would fail simply by disabling javascript. – user113716 Commented Oct 18, 2010 at 13:57

6 Answers 6

Do it server side ...

The logic you present, seems to fit better at the server side, if you really want to avoid the loading of the page pletely..

simply write your script in the script tag as a first element in body tag:

-- updated --

for hiding other page elements, use div with full width and height, if you want to show the page, hide the div, that will fix the problem

You can't run a script before the page loads (without messing up the document type), but you can put the script early in the page, i.e. in the head section.

You can't stop the page from loading until your script has finished. The page will continue to load in the background, but it will not render until the script has finished.

If you do a redirect in your script, the page will stop loading, but what's already loaded will render while waiting for the new response to arrive.

Script tags are execute as soon as they are encountered. Just put your script tag early, and then use a redirect if your condition is true. Hooking the window.onload event handler is how you get Javascript to trigger on load.

Is it possible for you to serve a page initially which contains merely the JavaScript which you need to execute within an HTML document? You can then request the page you want based on the result of the JavaScript.

You could use the jQuery load() method to load a part of a page conditionally, which is not running script before the DOM is ready, but may achieve what you want to do.