JavaScript Examples Bible - UserWorks Technologies

294
JavaScript Examples Bible: The Essential Companion to JavaScript Bible
Methods
appendData(“text”)
deleteData(offset, count)
insertData(offset, “text”)
replaceData(offset, count, “text”)
substringData(offset, count)
TextNode.appendData()
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓
Example
The page created by Listing 19-8 is a working laboratory that you can use to
experiment with the five data-related methods in NN6+. The text node that invokes
the methods is a simple sentence in a P element. Each method has its own clickable
button, followed by two or three text boxes into which you enter values for method
parameters. Don’t be put off by the length of the listing. Each method’s operation is
confined to its own function and is fairly simple.
Each of the data-related methods throws exceptions of different kinds. To help
handle these errors gracefully, the method calls are wrapped inside a try/catch
construction. All caught exceptions are routed to the handleError() function
where details of the error are inspected and friendly alert messages are displayed
to the user. See Chapter 39 of the JavaScript Bible for details on the try/catch
approach to error handling in W3C DOM-capable browsers.
Listing 19-8: Text object Data Method Laboratory
Data Methods of a W3C Text Object
function doAppend(form) {
var node = document.getElementById(“myP”).firstChild
var newString = form.appendStr.value
try {
node.appendData(newString)
}
catch(err) {
handleError(err)
}
}
function doDelete(form) {
var node = document.getElementById(“myP”).firstChild
var offset = form.deleteOffset.value