Here's what worked for me:
var clicked = {}
$("[contenteditable='true']").each(function(){
var id = $(this).attr("id");
$(this).bind('focus', function() {
// store the original value of element first time it gets focus
if(!(id in clicked)){
clicked[id] = $(this).html()
}
});
});
// then once the user clicks on save
$("#save").click(function(){
for(var id in clicked){
var original = clicked[id];
var current = $("#"+id).html();
// check if value changed
if(original != current) save(id,current);
}
});