JavaScript Examples Bible - UserWorks Technologies

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JavaScript Examples Bible: The Essential Companion to JavaScript Bible
windowObject.closed
can be written to it. The delay (using the setTimeout() method described later in
this chapter) invokes the finishNewWindow() function, which uses the global
newWind variable to reference the window for writing. The document.close()
method closes writing to the document — a different kind of close than a window
close.
A separate function, closeWindow(), is responsible for closing the subwindow.
To accommodate Internet Explorer 3, the script appears to create another window
with the same characteristics as the one opened earlier in the script. This is the
trick: If the earlier window exists (with exactly the same parameters and a name
other than an empty string), Internet Explorer does not create a new window even
with the window.open() method executing in plain sight. To the user, nothing
unusual appears on the screen. Things look weird for Internet Explorer 3 users only
if the user has closed the subwindow. The window.open() method momentarily
creates that subwindow. This subwindow is necessary because a “living” window
object must be available for the upcoming test of window existence. (Internet
Explorer 3 displays a script error if you try to address a missing window, while
NN2+ and IE4+ simply return friendly null values.)
As a final test, an if condition looks at two conditions: 1) if the window object
has ever been initialized with a value other than null (in case you click the window
closing button before ever having created the new window) and 2) if the window’s
closed property is null or false. If either condition is true, the close() method
is sent to the second window.
Listing 16-4: Checking Before Closing a Window
window.closed Property
// initialize global var for new window object
// so it can be accessed by all functions on the page
var newWind
// set flag to help out with special handling for window closing
var isIE3 = (navigator.appVersion.indexOf(“MSIE 3”) != -1) ? true : false
// make the new window and put some stuff in it
function newWindow() {
newWind = window.open(“”,”subwindow”,”HEIGHT=200,WIDTH=200”)
// take care of Navigator 2
if (newWind.opener == null) {
newWind.opener = window
}
setTimeout(“finishNewWindow()”, 100)
}
function finishNewWindow() {
var output = “”
output += “A Sub-window”
output += “”