Passing Javascript Associative Array to PHP using Jquery Ajax

[Amr87]

Hello Everyone, I`m Using this code to pass javascript associative array to php using jquery ajax

function install (loc) {
		var mydata = [];
		//lightbox();
		switch(loc){
		case "step1": 
		{ 
		 mydata['step'] = '1';
		 mydata['SiteName'] = $("#siteName").val();
		 mydata['SiteDesc'] = $("#siteDesc").val();
		 mydata['AdminEmail'] = $("#adminEmail").val();
		 mydata['username'] = $("#username").val();
		 mydata['password'] = $("#password").val();
        
		}
		break;
		case "step2":
		{
		mydata = [];
		}
		break;
		case "step3":
		{
		mydata = [];
		}
		break;
		case "step4":
		{
		mydata = [];
		}
		break;
		default : "error";
		}

		$.ajax({
		type: 'POST',
		url: 'install.php',
		data: {
		DataArray:mydata
		},
		dataType:'html',
		success: function (data) {
		$("#popupMSG").html(data);
		},
		error:function (data){

		}
		});

		}

in install.php I`m doing this test

<?php
$result = $_POST['DataArray'];
echo $result[0];


?>

but I get error :
Notice: Undefined index: DataArray in C:\wamp\www\Tests\test1\installation\install.php on line 2

whats wrong with this code ? can anyone help?