How to Run a jQuery or JavaScript Before Page Start to Load

Question

I have a script that I want to run before the page start to load  The script checks the value of a variable and depending on the value  redirect the user to a new page   I can successfully check the variable and redirect if needed but the page still loads and display empty page but then quickly redirects to the other page  I don t want that empty page to be displayed on the page at all before the redirect   Thank you  Ver

User · Answer

Hide the body with css then show it after the page is loaded:

CSS:

html { visibility:hidden; }

Javascript

$(document).ready(function() {
  document.getElementsByTagName("html")[0].style.visibility = "visible";
});

The page will go from blank to showing all content when the page is loaded, no flash of content, no watching images load etc.

User · Answer

If you don t want anything to display before the redirect  then you will need to use some server side scripting to accomplish the task before the page is served  The page has already begun loading by the time your Javascript is executed on the client side   If Javascript is your only option  your best best is to make your script the first  js file included in the  lt head gt  of your document   Instead of Javascript  I recommend setting up your redirect logic in your Apache or nginx server configuration     Apache s mod rewrite documentation nginx s HttpRewriteModule documentation

User · Answer

Don t use   document  ready   just put the script directly in the head section of the page  Pages are processed top to bottom so things at the top are processed first

User · Answer

Try the unload event  The unload event is sent to the window element when the user navigates away from the page      window   unload function           do something

User · Answer

lt head gt     lt script gt      if condition         window location    http   yournewlocation com            lt  script gt   lt  head gt   lt body gt         lt  body gt    This will force the checking of condition and the change in url location before the page renders anything  It is worth noting that you will specifically want to do this before the call to the jQuery library so you can avoid all that library loading  Some might also argue that this would be better placed in a wrapper method and called so here is that method   function redirectHandler condition  url     if condition       window location   url     else      return false          That would allow you to check multiple conditions and redirect to different locations based on it   if redirectHandler nologgedin    login php    redirectHandler adminuser    admin php       or if you only need it to run once and only once  but you like having nothing in the global namespace    function condition  url     if condition window location url      loggedin    login asp

User · Answer

Maybe you are using     document  ready function          Your code here        Try this instead   window onload   function

User · Answer

This should do the trick   window onload   function event        event stopPropagation true       window location href  http   www google com        Good luck  nbsp

[javascript] How to Run a jQuery or JavaScript Before Page Start to Load

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