Need Javascript to read CGI output

**monostone** · 12-30-2008 02:57 PM

I have a server with a .CGI on it than can be invoked by putting something like:
http://172.16.0.78/variable.cgi?variable=current_julian

into the address bar of a browser. This displays a single line of text that is the value of the requested variable, like 1230667891 in this case.

I need to make a javascript on another server, that will access this .CGI on the first server, and rather than displaying the value, I want it to assign the output to a variable in my script.

I've been trying things like:

var cjul='';

But I'm not having any luck. Any ideas would be much appreciated.

**jasonahoule** · 12-30-2008 04:28 PM

You can use the XMLHttpRequest to get the data. You can try something like this...

Code:

<script type="text/javascript">
	var openBodyTag = '<body>';
	var closeBodyTag = '</body>';

	function getText() {
		new Ajax.Request('/path/to/cgi/script',
				{
					method: 'get',
					parameters:{},
					onSuccess: function(transport) {
						html = transport.responseText;
						try {
							body = html.substr( (html.indexOf(openBodyTag) + openBodyTag.length), (html.indexOf(closeBodyTag) - (html.indexOf(openBodyTag) + closeBodyTag.length)));
							alert(body);
						} catch (err) {
							alert(err);
						}
					},
					onFailure:function(transport) {
						alert("error getting cgi output");
					}
				}
		);
	}
</script>

oops, forgot to mention that the above uses the prototype library and could be more effective with regex

**monostone** · 12-31-2008 10:20 AM

Thank you for your reply, but I'm still having trouble. When I run this, I should always get an alert window, shouldn't I? That isn't happening. And if I try a line like

document.write('<br>Text: '+html);

after executing the function, I get an error message saying html is undefined.

I'm sorry I don't know what regex is, but I did load the prototype framework v1.6.0.3 onto the server.

Also, when I was trying to learn what Ajax is, I saw this on a tutorial:

Did You Know? As a security measure, the XMLHTTPRequest object can generally only make calls to URLs within the same domain as the calling page and cannot directly call a remote server.

This makes me wonder if this even has a chance of working. What do you think?

**jasonahoule** · 12-31-2008 03:13 PM

Sorry, I missed the "another server" part. You could try using curl if you are using php.

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