JavaScript Examples Bible - UserWorks Technologies

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JavaScript Examples Bible: The Essential Companion to JavaScript Bible
getElementById(“elementID”)
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓ ✓ ✓
Example
You can find many examples of this method in use throughout this book, but you
can take a closer look at how it works by experimenting in The Evaluator (Chapter
13 in the JavaScript Bible). A number of elements in The Evaluator have IDs
assigned to them, so that you can use the method to inspect the objects and their
properties. Enter the following statements into both the top and bottom text fields
of The Evaluator. Results from the top field are references to the objects; results
from the bottom field are lists of properties for the particular object.
document.getElementById(“myP”)
document.getElementById(“myEM”)
document.getElementById(“myTitle”)
document.getElementById(“myScript”)
As you see in the Results field, NN6 is more explicit about the type of HTML element
object being referenced in the top text field than IE5. But nevertheless, both
browsers are pointing to the same objects.
getElementsByName(“elementName”)
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓ ✓ ✓
Example
Use The Evaluator to test out the getElementsByName() method. All form elements
in the upper part of the page have names associated with them. Enter the following
statements into the top text field and observe the results:
document.getElementsByName(“output”)
document.getElementsByName(“speed”).length
document.getElementsByName(“speed”)[0].value
You can also explore all of the properties of the text field by typing the following
expression into the bottom field:
document.getElementsByName(“speed”)[0]
document.getElementsByName()