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I am pretty new to creating web applications, so I am very unfamiliar with working over a web server. Just to let everyone know, I am implementing html, javascript, strawberry perl, AJAX, and running over an APACHE 2 web server. I finally have my web app working, I have an html file that calls a perl script that is in my htdocs directory. Here is a mock up of my .html file for reference, this one simply alerts the user of the output printed by the perl script:

<!DOCTYPE html>
<html>
<head>
<script>


function loadXMLDoc() {
var xmlhttp;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
    xmlhttp.onreadystatechange=function()
{
var str;
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
// Get output from perl script and print it
str = xmlhttp.responseText;
alert(str);
}
}
xmlhttp.open("GET","http://localhost/try.pl" , false); //perl script
xmlhttp.send();
}
</script>
</head>
<body>

<h2>Example</h2></div>
<button type="button" onclick="loadXMLDoc()">Display</button>

</body>
</html>

So this file test.html calls a perl script [try.pl] within the same directory. Also, the perl script just prints a number so this alerts the user of the number. This is just an example of my implementation. My actual perl script and java script [inside the ready state block] is much more complicated. Now I have to add functionality to my web app, so to my questions:

  1. I am looking to run a second and separate perl script when a different event happens. For example, when a button is clicked this perl script is being ran. I am going to have another different event, say a double click on an icon or something, that will need to call this second perl script. Will I simply have the new event call a different function [the first is called Loadxmldoc()] that is almost identical to the one I have here except it will have different code in the ready state block and call a different perl script at the end of it? I am a little confused as to how to implement this.

  2. Also, If I have a list of file names within my javascript code, I need to process EACH of the files using a perl script. Currently I am only processing one so calling the perl script as I have here is fine. I have looked all over the internet to try to find how I would do this but it seems every explanation just covers how to call "a" CGI script. So within my code, say where I am "alerting" the user, I am going to have an array that stores the file names. I need to iterate over this array and for each filename [array element] I need to call the same perl script to process that file. How should I go about implementing this? Currently, my html file is only calling the perl script once and I do not know how I could call it for EACH file since my GET command is outside of my ready state block...

Any help or direction would be appreciated. I am expected to deliver soon and have been spending way too much time sifting through repetitive examples that haven't helped me...:/

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1 Answer 1

up vote 0 down vote

As far as generalizing your AJAX request, you can create a function (or rather, a set of functions) that would process different types of responses, as follows:

var requests = [];
requests['script1'] = "http://localhost/try.pl";
requests['script2'] = "http://localhost/try2.pl";
var response_processing = [];
response_processing['script1'] = function (xmlhttp) {
    var str = xmlhttp.responseText;
    alert(str);
};
// Here, you can add more functions to do response processing for other AJAX calls, 
under different map keys.

Now, in your AJAX code, you call an appropriate request AND appropriate response processor, based on your script name (passed to loadXMLDoc() call as follows): loadXMLDoc("script1");

function loadXMLDoc(script_name) {

    // Your generic AJAX code as you already implemented

    if (xmlhttp.readyState==4 && xmlhttp.status==200) {
        response_processing[script_name](xmlhttp);
        // Careful so script_name doesn't get closured in onreadystatechange()
    }
    }
    xmlhttp.open("GET", requests[script_name], false); //perl script
    xmlhttp.send();
}
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