[DustyD]

Hi there, I am having trouble passing a variable via POST through a xmlhttp request: I have a main page index.php and in there a form that contains a textarea and a submit button.

In index.php:

echo <<< SEARCH
	<div align="center">
		<form name="SearchBar" method="post" action="index.php?"> 
  			<div align="center"> 
     			<textarea id="textinput" name="qinput" cols="80" rows="4" onclick="request_information('test',this.value)">$mesg</textarea>
				<input type="submit" name="SearchButton" value="Search" /> 
			</div> 
		</form>
	</div>
SEARCH;

I linked a javascript file that contains the "request_information" function:

// service request function
function request_information( element_id,str )
{
	// get the object used to do 
	var xmlhttp;
	//var element_id = "test";
	if (window.XMLHttpRequest)
	{
		xmlhttp=new XMLHttpRequest();
	}
	else
	{
 		xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
 	}
 	
 	// message while waiting
 	document.getElementById(element_id).innerHTML = "<p> request_information: Searching...</p>";
 	
 	// assign the request callback
 	xmlhttp.onreadystatechange=function()
  	{
  		if (xmlhttp.readyState==4 && xmlhttp.status==200)
    	{
    		document.getElementById(element_id).innerHTML="<p> request_information:" + xmlhttp.responseText + "</p>";
    	}else
    	{
    		document.getElementById(element_id).innerHTML= "<p> request_information: Failed</p>";
    	}
  	}
 	var query_str = "helluuuu";	
 	xmlhttp.open("POST","cat.php?qu="+query_str,true);
 	xmlhttp.send();
}

Here I'm trying the simplest case scenario by trying to pass the value of variable "query_str" to the "cat.php" file which contains:

<?php
	include "connect.php";
	
	// new process request
	$status = request_process(0);
	
	$q = "";
	if (isset($_POST["qu"]))
		$q = $_POST["qu"];
	else
		$q = "qu not passed";
	echo <<<yea

<h5> PID: $status </h5>
<h5> Query: $q </h5>

yea;
?>

I always get "qu not passed" where I print output. Before I handled the error with if statements I was getting "Undefined index 'qu' in 'cat.php' refered from 'index.php?'" in apache2 error log. Also, the 'this.value' parameter I pass doesn't work neither. All these files are in the same directory except the javascript file which is in a js/ directory..

According to W3C examples, this should work. Have I missed something crucial here?

Thankyou for your help!
dustyd

[JackOfAllTrades]

You're not passing it as a POST variable, you're passing it in the URL, making it available through the GET superglobal array. For a POST request you need to send the data not in the URL, but in the send() function, and set the appropriate HTTP headers.

For you to read.

[DustyD]

Thankyou JackOfAllTrades, that was incredibly accurate and useful information. Everything works as expected.