jQuery: How to detect window width on the fly?

I have a scrolling element on my page (with the jScrollPane jQuery plugin). What I want to accomplish is a way to turn off the scrolling window by detecting the width of the browser window. I am doing a responsive layout and I want this scrolling feature to be turned off when the browser is below a certain width. I am able to make it work when I refresh the page, but when I resize the browser window the width value does not update on the fly.

Right now if I start out with a window that is 1000px wide then resize to 350px the scroll feature remains. I want the scroll feature to shut off as soon as the browser width hits 440px.

Here's the code I have so far..

var windowsize = $(window).width();

$(window).resize(function() {
  var windowsize = $(window).width();
});

if (windowsize > 440) {
  //if the window is greater than 440px wide then turn on jScrollPane..
    $('#pane1').jScrollPane({
       scrollbarWidth:15, 
       scrollbarMargin:52
    });
}

Changing a variable doesn't magically execute code within the if-block. Place the common code in a function, then bind the event, and call the function:

$(document).ready(function() {
    // Optimalisation: Store the references outside the event handler:
    var $window = $(window);
    var $pane = $('#pane1');

    function checkWidth() {
        var windowsize = $window.width();
        if (windowsize > 440) {
            //if the window is greater than 440px wide then turn on jScrollPane..
            $pane.jScrollPane({
               scrollbarWidth:15, 
               scrollbarMargin:52
            });
        }
    }
    // Execute on load
    checkWidth();
    // Bind event listener
    $(window).resize(checkWidth);
});

Put your if condition inside resize function:

var windowsize = $(window).width();

$(window).resize(function() {
  windowsize = $(window).width();
  if (windowsize > 440) {
    //if the window is greater than 440px wide then turn on jScrollPane..
      $('#pane1').jScrollPane({
         scrollbarWidth:15, 
         scrollbarMargin:52
      });
  }
});

Below is what i did to hide some Id element when screen size is below 768px, and show up when is above 768px. It works great.

var screensize= $( window ).width();

if(screensize<=768){
		if($('#column-d0f6e77c699556473e4ff2967e9c0251').length>0)
			{
				$('#column-d0f6e77c699556473e4ff2967e9c0251').css('display','none');
			}
}
else{
		if($('#column-d0f6e77c699556473e4ff2967e9c0251').length>0)
			{
				$('#column-d0f6e77c699556473e4ff2967e9c0251').removeAttr( "style" );
			}

}
changething = function(screensize){
		if(screensize<=768){
			if($('#column-d0f6e77c699556473e4ff2967e9c0251').length>0)
			{
				$('#column-d0f6e77c699556473e4ff2967e9c0251').css('display','none');
			}
		}
		else{
		if($('#column-d0f6e77c699556473e4ff2967e9c0251').length>0)
			{
				$('#column-d0f6e77c699556473e4ff2967e9c0251').removeAttr( "style" );
			}

		}
}
$( window ).resize(function() {
 var screensize= $( window ).width();
  changething(screensize);
});

> I dont know if this useful for you when you resize your page:

$(window).resize(function() {
       if(screen.width == window.innerWidth){
           alert("you are on normal page with 100% zoom");
       } else if(screen.width > window.innerWidth){
           alert("you have zoomed in the page i.e more than 100%");
       } else {
           alert("you have zoomed out i.e less than 100%");
       }
    });