JavaScript Examples Bible - UserWorks Technologies

286
JavaScript Examples Bible: The Essential Companion to JavaScript Bible
Range.insertNode()
property of the undoBuffer global variable object). After that, the selection is
deleted from the document tree, leaving the selection as a collapsed insertion
point. A copy of that selection in the form of a range object is preserved in the
undoBuffer object so that the undo script knows where to reinsert the original
text. A new text node is created with an uppercase version of the original text, and,
finally, the insertNode() method is invoked to stick the converted text into the
collapsed range.
Undoing this operation works in reverse. Original locations and strings are
copied from the undoBuffer object. After creating the range with the old start and
end points (which represent a collapsed insertion point), the resurrected text (converted
to a text node) is inserted into the collapsed range. For good housekeeping,
the undoBuffer object is restored to its unused form.
Listing 19-5: Inserting a Node into a Range
NN Selection Object Replacement
var undoBuffer = {rng:null, txt:””}
function convertSelection() {
var sel, grossRng, netRng, newText
try {
sel = window.getSelection()
if (!sel.isCollapsed) {
grossRng = sel.getRangeAt(0)
undoBuffer.txt = grossRng.toString()
sel.deleteFromDocument()
netRng = sel.getRangeAt(0)
undoBuffer.rng = netRng
newText = document.createTextNode(undoBuffer.txt.toUpperCase())
netRng.insertNode(newText)
}
}
catch(err) {
alert(“Vital Range object services are not yet implemented in this
browser.”)
}
}
function undoConversion() {
var rng, oldText
if (undoBuffer.rng) {
rng = document.createRange()
rng.setStart(undoBuffer.rng.startParent, undoBuffer.rng.startOffset)
rng.setEnd(undoBuffer.rng.endParent, undoBuffer.rng.endOffset)
oldText = document.createTextNode(undoBuffer.txt)
rng.insertNode(oldText)
undoBuffer.rng = null
undoBuffer.txt = “”
}
}