JavaScript Examples Bible - UserWorks Technologies

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JavaScript Examples Bible: The Essential Companion to JavaScript Bible
popupObject.hide()
If you then click into the main window to hide the pop-up, you will see a different
result if you enter the following statement into the top text box by itself:
alert(“Popup is open:” + a.isOpen)
Methods
hide()
show(left, top, width, height[,
positioningElementRef])
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓
Example
Listing 16-49 demonstrates both the show() and hide() methods for a popup
object. A click of the button on the page invokes the selfTimer() function, which
acts as the main routine for this page. The goal is to produce a pop-up window that
“self-destructs” five seconds after it appears. Along the way, a message in the popup
counts down the seconds.
A reference to the pop-up window is preserved as a global variable, called
popup. After the popup object is created, the initContent() function stuffs the
content into the pop-up by way of assigning style properties and some innerHTML
for the body of the document that is automatically created when the pop-up is generated.
A SPAN element is defined so that another function later on can modify the
content of just that segment of text in the pop-up. Notice that the assignment of
content to the pop-up is predicated on the pop-up window having been initialized
(by virtue of the popup variable having a value assigned to it) and that the pop-up
window is not showing. While invoking initContent() under any other circumstances
is probably impossible, the validation of the desired conditions is good programming
practice.
Back in selfTimer(), the popup object is displayed. Defining the desired size
requires some trial and error to make sure the pop-up window comfortably accommodates
the text that is put into the pop-up in the initContent() function.
With the pop-up window showing, now is the time to invoke the countDown()
function. Before the function performs any action, it validates that the pop-up has
been initialized and is still visible. If a user clicks the main window while the
counter is counting down, this changes the value of the isOpen property to false,
and nothing inside the if condition executes.
This countDown() function grabs the inner text of the SPAN and uses
paresInt() to extract just the integer number (using base 10 numbering, because
we’re dealing with zero-leading numbers that can potentially be regarded as octal
values). The condition of the if construction decreases the retrieved integer by
one. If the decremented value is zero, then the time is up, and the pop-up window is