JavaScript Examples Bible - UserWorks Technologies

Chapter 1 ✦ Generic HTML Element Objects (Chapter 15)
for different types of event processing. The srcElement property is used initially as
a filter to decide whether the status bar will reveal further processing about the
TEXTAREA element’s event details.
The onMouseDown event handler in the BODY element triggers all event processing.
IE events bubble up the hierarchy (and no events are cancelled in this page), so
all mouseDown events eventually reach the BODY element. Then, the
whereInWorld() function can compare each mouseDown event from any element
against the textarea’s geography.
Listing 15-24: Using the componentFromPoint() Method
componentFromPoint() Method
function whereInWorld(elem) {
var x = event.clientX
var y = event.clientY
var component = document.all.myTextarea.componentFromPoint(x,y)
if (window.event.srcElement == document.all.myTextarea) {
if (component == “”) {
status = “mouseDown event occurred inside the element”
} else {
status = “mouseDown occurred on the element\’s “ + component
}
} else {
status = “mouseDown occurred “ + component + “ of the element”
}
}
componentFromPoint() Method
Tracking the mouseDown event relative to the textarea object. View results in
status bar.
This is Line 1
This is Line 2
This is Line 3
This is Line 4
This is Line 5
This is Line 6
63
elementObject.componentFromPoint()