Javascript - Redirect
You're moving to a new domain name. You have a time-delay placeholder on your download site. You have a list of external web servers that are helping to mirror your site. What will help you deal with and/or take advantage of these situations? JavaScript redirects will.
When your webpage is moved, you'd probably want to notify your visitors of the change. One good way is to place a "redirect page" at the old location which, after a timed delay, will forward visitors to the new location of your webpage. You can do just this with a JavaScript redirection.
window.location
Control over what page is loaded into the browser rests in the JavaScript property window.location. By setting window.location equal to a new URL, you will in turn change the current webpage to the one that is specified. If you wanted to redirect all your visitors to www.google.com when they arrived at your site, you would just need the script below:
JavaScript window.location Example
<script type="text/javascript">
<!--
window.location = "http://www.google.com/"
//-->
</script>
Implementing a timed delay in JavaScript is useful in the following situations:
- Showing an "Update your bookmark" page when you have to change URLs or page locations
- For download sites that wish to have a timed delay before the download starts
- To refresh a webpage once every specified number of seconds
The code for this timed delay is slightly involved and is beyond the scope of this tutorial. However, we have tested it and it seems to function properly.
JavaScript Time Delay Example
<html>
<head>
<script type="text/javascript">
<!--
function delayer(){
window.location = "../javascriptredirect.php"
}
//-->
</script>
</head>
<body onLoad="setTimeout('delayer()', 5000)">
<h2>Prepare to be redirected!</h2>
<p>This page is a time delay redirect, please update your bookmarks to our new location!</p>
</body>
</html>
The most important part of getting the delay to work is being sure to use the JavaScript function setTimeout. We want the delayer() function to be used after 5 seconds or 5000 milliseconds (5 seconds), so we pass the setTimeout() two arguments.
- 'delayer()' - The function we want setTimeout() to execute after the specified delay.
- 5000 - the number of millisecods we want setTimeout() to wait before executing our function. 1000 miliseconds = 1 second.
Note: Do use JavaScript for redirections when you change your website's URL or move a file to a new location. Don't use redirections when they can easily be replaced with a normal HTML hyperlink.
