[SOLVED] trying to get a js var into php

cha0sriderx · October 26, 2007

im trying to figure out the width of the screen and in order to do that you have to use javascript or atleast thats the only way i know how to do it. well i want to take the width and then subtract 150 from it. well it threats the width as a str and not an int value.

<?
  function getwidth(){
    $swidth = '<script language="javascript">document.write(screen.width);</script>';
    return $swidth;
  }
  $width = getwidth();

  $middlewidth = "$width - 150";
  echo "$width / $middlewidth";
?>

cha0sriderx · October 26, 2007

well i know why that wont work, it displays the number after it does the command. i finally decided to view source:P. but is there any other way to go about doing this?

for some reason it wouldnt let me edit my first post. sorry for the double post.

putty · October 26, 2007

I use AJAX to send variables between Javascript and PHP, this is a good tutorial to get you started. http://www.tizag.com/ajaxTutorial/

teng84 · October 26, 2007

yah thats hard using php

hmm maybe you can use GET variables

function open_win()

{

var x =screen.width;

window.open("http://www.teng84.com?width="+x)

}

cha0sriderx · October 28, 2007

ive never messed with ajax, do you think its possible you can give me an example code for sending a javascript variable to php?

putty · October 29, 2007

Basically your script is in two parts the JavaScript and your PHP code

JavaScript

<html>
<body>

<script language="javascript" type="text/javascript">
<!--
//Browser Support Code
function ajaxFunction(javaValue){
var ajaxRequest;  // The variable that makes Ajax possible!

try{
	// Opera 8.0+, Firefox, Safari
	ajaxRequest = new XMLHttpRequest();
} catch (e){
	// Internet Explorer Browsers
	try{
		ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
	} catch (e) {
		try{
			ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
		} catch (e){
			// Something went wrong
			alert("Your browser broke!");
			return false;
		}
	}
}
// Create a function that will receive data sent from the server
ajaxRequest.onreadystatechange = function(){
	if(ajaxRequest.readyState == 4){
		var ajaxDisplay = document.getElementById('ajaxDiv');
		ajaxDisplay.innerHTML = ajaxRequest.responseText;
	}
}
var queryString = "?javaValue=" + javaValue;
ajaxRequest.open("GET", "php.php" + queryString, true);
ajaxRequest.send(null);
}

//-->
</script>



<form name='myForm'>
<input type='button' onclick='ajaxFunction(28)' value='Sent Value To PHP' />
</form>
<div id='ajaxDiv'>Your result will display here</div>
</body>
</html>

PHP

<?php
$javaScript_value = $_GET['javaValue'];
echo "The Value Past from PHP to jacaScript was $javaScript_value";
?>

ajaxFunction(28), the 28 will be passed to php

the JavaScript value will be passed via

var queryString = "?javaValue=" + javaValue;

you can pass more than one variable

var queryString = "?javaValue=" + javaValue + "&other=" + value;

Sorry for the rough explanation but I’m a little shoer on time. The best way to learn ajax is to do a few tutorials.

kenrbnsn · October 29, 2007

I use the Yahoo! User Interface libraries when I want to use AJAX techniques.

Here's some very basic code that gets the screen width into PHP:

<?php
session_start();
if (isset($_POST['vpw'])) {  // $_POST['vpw'] holds the value obtained in Javascript
	$_SESSION['vpw'] = $_POST['vpw'];
	exit('Ok');
}
?>
<html>
<head>
<title>Your title here</title>
<script src="http://yui.yahooapis.com/2.3.1/build/yahoo/yahoo-min.js"></script>
<script src="http://yui.yahooapis.com/2.3.1/build/dom/dom-min.js"></script>
<script src="http://yui.yahooapis.com/2.3.1/build/event/event-min.js"></script>
<script src="http://yui.yahooapis.com/2.3.1/build/connection/connection-min.js"></script>
<script type="text/javascript">

var cbnull = function(o) {
	var resp= o.responseText;
	alert(resp);   // debug
}

var cb =
{
       success:cbnull,
       failure:cbnull
}

function init() {
	pass_str = 'trace=1&vpw=' + YAHOO.util.Dom.getViewportWidth();
	gc = YAHOO.util.Connect.asyncRequest('POST','<?php echo $_SERVER['PHP_SELF'] ?>',cb,pass_str);
       }
        YAHOO.util.Event.onDOMReady(init);	
        </script>
</head>
<body>
<?php echo '<pre>' . print_r($_SESSION,true) . '</pre>'; ?>
</body>

This code has been tested and works.

Ken

cha0sriderx · October 29, 2007

thanks both of you guys for your help, i used ken's since it didnt require a form.

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[SOLVED] trying to get a js var into php

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