javascript - elementFromPoint select bottom element

Question

I\'m working on this drag and drop application with jquery/javascript, and I\'m having to use a balance of the two to accomplish what I want.

var drop = docume

Answer 1

Since document.elementFromPoint returns the topmost element, you'll need to temporarily set your draggable to display:none or pointer-events:none to find elements below it. I've created a gist below that returns a list of all elements at a given point.

try

var elementsArray = KoreSampl.atPoint(x,y,yourTableElement);

or

var elementsArray = KoreSampl.fromEvent(dropEvent, yourTableElement);

then

for(var i=0; i<elementsArray.length; i++) {
   //loop through elementsArray until you find the td you're interested in

}

Using the gist below: https://gist.github.com/2166393

;(function(){
    //test for ie: turn on conditional comments
    var jscript/*@cc_on=@_jscript_version@*/;
    var styleProp = (jscript) ? "display" : "pointerEvents";

    var KoreSampl = function() {};
    KoreSampl.prototype.fromEvent = function(e, lastElement) {
        e = e || window.event; //IE for window.event
        return this.atPoint(e.clientX, e.clientY, lastElement);
    };
    KoreSampl.prototype.atPoint = function(clientX, clientY, lastElement) {
        //support for child iframes
        var d = (lastElement) ? lastElement.ownerDocument : document;
        //the last element in the list
        lastElement = lastElement || d.getElementsByTagName("html")[0];

        var element = d.elementFromPoint(clientX, clientY);
        if(element === lastElement || element.nodeName === "HTML") {
            return [element];
        } else {
            var style= element.style[styleProp];
            element.style[styleProp]="none"; //let us peak at the next layer
            var result = [element].concat(this.atPoint(clientX,clientY,lastElement));
            element.style[styleProp]= style; //restore
            return result;
        }
    };
    window["KoreSampl"] = new KoreSampl();
})(); 

Answer 2

If you can dispense with older browsers, the following CSS will work:

Just apply this rule to your to your topmost element that is being dragged.

#dragging {
  pointer-events: none;
}