February 7, 2000 - Which Frame was Clicked? | WebReference

February 7, 2000 - Which Frame was Clicked?

Yehuda Shiran February 7, 2000
Which Frame was Clicked?
Tips: February 2000

Yehuda Shiran, Ph.D.
Doc JavaScript

Imagine, in a framed page, you want to decide at the application's top window which child frame has been clicked. One of the ways to do it as follows.

We put an event handler for mouse clicks in the child frame:

  <A HREF="javascript:void(0)" onClick="handleClick()">
     <IMG SRC="doc.gif" 
          WIDTH="50" HEIGHT="50" BORDER="0"></A>

The event handler handleClick() is defined via a function that is included in the top frame:

function handleClick() {

The findClickedBox() function (included in the top frame) finds which frame has been clicked:

function findClickedBox(boxObject) {
 for (var i = 0; i < dim1; i++) {
  for (var j = 0; j < dim2; j++) {
   if (boxObject == top.frames[i].frames[j]) {
    rowFound = j;
    colFound = i;
    if (blockClicking == false)
    if (top.frames[i].frames[j].document.images[0].src.indexOf(blank) == -1)
       revealBox(rowFound, colFound);

We pass the self object from the lowest frame to the top frame. The self object is like an ID by which we can identify the clicked box. We go over all the frames and check for equality between their frame objects and the object passed from the clicked box. Once we determine the clicked frame, we set the rowFound and colFound variables.

Learn more about a frame-based application in Column 37, JavaScript and Frames, Part II - The Famous Memory Game.