JavaScript Examples Bible - UserWorks Technologies

Chapter 2 ✦ Window and Frame Objects (Chapter 16)
The window.open() method doesn’t provide parameters for setting the new
window’s background color, so I let the getColor() function in the new window do
the job as the document loads. The function uses the opener property to find out
which radio button on the main page is selected.
Listing 16-12: References to the opener Property
New Window on the Block
function getColor() {
// shorten the reference
colorButtons = self.opener.document.forms[0].color
// see which radio button is checked
for (var i = 0; i < colorButtons.length; i++) {
if (colorButtons[i].checked) {
return colorButtons[i].value
}
}
return “white”
}
document.write(“”)
This is a new window.
Type text here for the main window:
In the getColor() function, the multiple references to the radio button array
can be very long. To simplify the references, the getColor() function starts out by
assigning the radio button array to a variable I arbitrarily call colorButtons. That
shorthand now stands in for lengthy references as I loop through the radio buttons
to determine which button is checked and retrieve its value property.
A button in the second window simply fetches the title of the opener window’s
document. Even if another document loads in the main window in the meantime,
the opener reference still points to the main window: Its document object, however,
will change.
143
windowObject.opener