How would I post a Javascript variable to my PHP file to use?

Question

I am very unfamiliar with PHP and doing posting with Javascript. I have two .php files that I am using - one is my main .php file called page.tpl.php and the other is the php file that has my Javascript in it called winWidth.php . I want to POST the window width of the browser to my page.tpl.php and then use it to conditionally sort of if a window width is larger than 768 .

I am getting the window width just fine in my winWidth.php :

var w = window.innerWidth;

But I am not sure what I need to do with it next. Nor am I sure what to do with it in my page.tpl.php .

Any help would be much appreciated, thanks!

Answer 1

I answered this on a simliar Question here

But what you need ist an Ajax Call from JavaScript with jQuery, it would look like this

$.ajax({
            type: "POST",
            dataType: 'json',
            url: yourfile.php,
            data: {data : data}
        })
        .done(function(response){
            //do something with your code like document.wirte(response)
        })
        .fail(function(jqXHR, textStatus, errorThrown){
            alert('Error : ' + errorThrown); //Error handling
        });

In plain JavaScript you could do the following

EDIT

var xmlhttp;
var data; //The Data you need to transmit to the php file
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()
{
    if (xmlhttp.readyState==4 && xmlhttp.status==200)
        {
            //do something
        }
    }
    xmlhttp.open("POST",'yourfile',true);
    xmlhttp.send(data);
}

You can take the given data in PHP then with

$data = $_POST['data'];