Help with js file exists query

Question

First let me acknowledge that I'm in way over my head. Our church website was dropped on me and I'm doing my best to get up to speed after about a 10 year hiatus. Currently undergoing pretty serious chemotherapy, so at least I have lots of time.

I am trying to figure out a way to script an html web page to check for the existence of another web page, and then display that other page if it is found. I found what looks to be a possible solution here but I can't seem to figure out to make it work.

We have a page for youth basketball which, upon loading, should check to see if a "games cancelled" page exists, and if so, display that page. i have some command line scripts ready that will allow the coaches to upload/delete the "cancelled" page, based on weather, via FTP.

I realize I'm probably asking for way too much help here, but please know it would be greatly appreciated.

Thanks very much

NeedyOldNoob

Answer 1

You do have access to any server-side scripting languages, such as PHP? It might be a lot easier for you to use PHP to do this instead of Javascript. Javascript is client-side, which means it lives in the user's browser and not on the server where your web page will be stored.

PHP is server side, so it will have a much easier time seeing if a file on your server exists or not.

Let me know if you have the ability to use PHP and we can go from there.

Answer 2

First you will need to include the jQuery library:

<script src="http://code.jquery.com/jquery-latest.js"&gt;&lt;/script&gt;

Next you will need to check if the page exists:

<script type="text/javascript">
var path = '/THIS_IS_THE_PATH_TO/YOUR_CANCELLED_PAGE.html';

$(function () { 
  $.ajax({ 
    url : path, 
    success : function() { 
        alert('The page was found');
        // redirect to page
        window.location = path;
    }, 
    error : function(xhr, d, e) { 
      if (xhr.status == 404) { 
        // page not found 
        alert('The page was not found');
      } 
    } 
  }); 
});
</script>

Answer 3

PHP is a lot easier to do things like this, it's also a lot faster and will also work with users who don't have Javascript enabled. Also, if you're looking for pages outside of your own domain, Javascript won't allow it because of the same-origin policy.

In the most simple form you could do something like this:

<?php
$page = file_get_contents("http://example.com/page_you_need.html");
if ($page) {
    echo $page;
} else {
    echo "Page does not exist!";
}
?>

Note that you can easily load malicious code using scripts like this, so be sure you trust the page you're trying to read and don't allow any user input in file_get_contents.