$(\"#dvMyDIV\").bind(\"resize\", function(){
alert(\"Resized\");
});
or
$(\"#dvMyDIV\").resize(function(){
alert(\"Resized\
I might suggest something like this:
1) on page load, get width of your div and put it in a global variable
2) on execution of whatever operation directly or implicitly resizes that div (which I assume is a javascript-driven event) check the new width against the old width and update the global value with the new width.