Chrome/V8 slow onmousemove() over certain elements
I'm going to answer my own question, as I've found a solution:
Running this jQuery function on the box fixed the lag issue:
$.fn.disableSelection = function() { return this.each(function() { $(this).attr('unselectable', 'on') .css({ '-moz-user-select':'none', '-webkit-user-select':'none', 'user-select':'none', '::selection':'none', }) .each(function() { this.onselectstart = function() { return false; }; }); });};
I see no lagging in my computer...
Anyway, perhaps you can try decreasing the frequency your event handler can be called by using something like underscore's throttle function