JavaScript Examples Bible - UserWorks Technologies

90 JavaScript Examples Bible: The Essential Companion to JavaScript Bible
Example
Use The Evaluator (Chapter 13 in the JavaScript Bible) to experiment with the
scrollIntoView() method. Resize the browser window height so that you can see
only the topmost text box and the Results textarea. Enter each of the following
statements into the top text box and see where the myP element comes into view:
myP.scrollIntoView()
myP.scrollIntoView(false)
Expand the height of the browser window until you can see part of the table
lower on the page. If you enter
myTable.scrollIntoView(false)
into the top text box, the page scrolls to bring the bottom of the table to the bottom
of the window. But if you use the default parameter (true or empty),
myTable.scrollIntoView()
the page scrolls as far as it can in an effort to align the top of the element as closely
as possible to the top of the window. The page cannot scroll beyond its normal
scrolling maximum (although if the element is a positioned element, you can use
dynamic positioning to place it wherever you want — including “off the page”).
Also, if you shrink the window and try to scroll the top of the table to the top of the
window, be aware that the TABLE element contains a CAPTION element so the caption
is flush with the top of the window.
setActive()
elementObject.setActive()
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓
Example
Use The Evaluator (Chapter 13 in the JavaScript Bible) to compare the
setActive() and focus() methods. With the page scrolled to the top and the window
sized so that you cannot see the sample check box near the bottom of the
page, enter the following statement into the top text box:
document.forms[1].myCheckbox.setActive()
Scroll down to see that the checkbox has operational focus (press the spacebar
to see). Now, scroll back to the top and enter the following:
document.forms[1].myCheckbox.focus()
This time, the checkbox gets focus and the page automatically scrolls the object
into view.