webserver connection check

[blasius]

Hi guys,

Is it possible to:
after pressing a button on a website witch is redirecting to a new site,
before redirecting to the new site, first check if the website is available,
if not available >> do not try to redirect to the new site.

Just a method to see if the web server (or website) is available before trying to download it.

if possible >> how?

thanks!

[boogyman]

umm that is basically asking it to connect 2 times?

[tech_support]

You could use PHP to do that, but definitely not JavaScript.

[Twey]

Actually, it can be done with Javascript. It shouldn't be, but it can.

[mburt]

first check if the website is available,

How can that be done with JavaScript?

file_exists works with PHP, that's the only plausible way of doing it.

[Twey]

How can that be done with JavaScript?

If you have the address of an image on that site:

var im = document.createElement("img");
im.src = "http://www.someothersite.com/images/image.png";
im.onload = function() {
  // The server is up.
};
im.onerror = function() {
  // The connection timed out, the server
  // isn't up (or there was a problem
  // accessing the image requested).
};

[shachi]

I think pear's Net_Ping package might help you.

http://pear.php.net/package/Net_Ping
http://builder.com.com/5100-6371-5234592.html

[Twey]

Not necessarily... just because the host is up, doesn't mean the webserver is. mburt is right, fsockopen() or file_exists() (the latter requires url_fopen enabled) are the better choices.

[mburt]

(the latter requires url_fopen enabled)

I swear. Every person who's ever been on the PHP forum has asked some sort of question involving this, at least ONCE.

Just a note for someone who's about to ask:
It's a command in your php.ini which is either, off or on. If it is on, it allows you to basically "connect" to other sites' data. If it's off, you're royally screwed.

[boxxertrumps]

What reasons would there be for turning it off?