Prevent selection in HTML

I have a div on a HTML page and whenever I press the mouse and move it, it will show that "can't drop" cursor like it selects something. Is there a way to disable selection? I tried CSS user-select with none without success.

The proprietary variations of user-select will work in most modern browsers:

*.unselectable {
   -moz-user-select: -moz-none;
   -khtml-user-select: none;
   -webkit-user-select: none;

   /*
     Introduced in IE 10.
     See http://ie.microsoft.com/testdrive/HTML5/msUserSelect/
   */
   -ms-user-select: none;
   user-select: none;
}

For IE < 10 and Opera, you will need to use the unselectable attribute of the element you wish to be unselectable. You can set this using an attribute in HTML:

<div id="foo" unselectable="on" class="unselectable">...</div>

Sadly this property isn't inherited, meaning you have to put an attribute in the start tag of every element inside the <div>. If this is a problem, you could instead use JavaScript to do this recursively for an element's descendants:

function makeUnselectable(node) {
    if (node.nodeType == 1) {
        node.setAttribute("unselectable", "on");
    }
    var child = node.firstChild;
    while (child) {
        makeUnselectable(child);
        child = child.nextSibling;
    }
}

makeUnselectable(document.getElementById("foo"));

It's seem CSS user-select don't prevent image drag and drop... so..

HTML :

<img src="ico.png" width="20" height="20" alt="" unselectable="on" /> Blabla bla blabla

CSS :

* {
	 user-select: none;
    -khtml-user-select: none;
    -o-user-select: none;
    -moz-user-select: -moz-none;
    -webkit-user-select: none;
}

::selection { background: transparent;color:inherit; }
::-moz-selection { background: transparent;color:inherit; }

JS :

$(function(){
    $('*:[unselectable=on]').mousedown(function(event) {
        event.preventDefault();
        return false;
    });
});

I use cancelBubble=true and stopPropagation() in the mouse down and move handlers.

event.preventDefault() seems to do the trick (tested in IE7-9 and Chrome) :

jQuery('#slider').on('mousedown', function (e) {
    var handler, doc = jQuery(document);
    e.preventDefault();
    doc.on('mousemove', handler = function (e) {
        e.preventDefault();
        // refresh your screen here
    });
    doc.one('mouseup', function (e) {
        doc.off('mousemove', handler);
    });
});

Have you got some sort of transparent image that your selecting? Usually the "cant drop" icon appears when you drag an image. Otherwise it normally selects text when you drag. If so you might have to put the image behind everything using z-index.