how can i add something in javascript that will check the website url of someone on a website and then redirect to a certain page on the website, if a match is found? for example...

the string we want to check for, will be mydirectory, so if someone went to mysite.com/mydirectory/anyfile.php or even mysite.com/mydirectory/index.php javascript would then redirect their page / url to mysite.com/index.php because it has mydirectory in the url, how can i do that using javascript?

• javascript
• javascript-events

If I have understood the question correctly, then it is fairly simple and can be achieved using document.URL

var search = 'mydirectory'; // The string to search for in the URL.
var redirect = 'http://mysite.com/index.php' // Where we will direct users if it's found
if(document.URL.substr(search) !== -1) { // If the location of 
    // the current URL string is any other than -1 (doesn't exist)
    document.location = redirect // Redirect the user to the redirect URL.
}

Using document.URL you can check anything in the URL, however you might want to look into using something like Apache's mod_rewrite for redirecting the user before they even load the page.

Check out window.location, particularly it's properties and methods. You would be interested in (part of the) pathname property (you can split it on /) and the href property to change the page.

This is all assuming the javascript is being served in the first place; so I'm assuming anyfile.php and index.php would all result in the JS being served and not some 'generic 404' message.