JavaScript Examples Bible - UserWorks Technologies

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JavaScript Examples Bible: The Essential Companion to JavaScript Bible
Listing 25-2 (continued)
Enter lowercase letters for conversion to uppercase:
I also show two other ways to accomplish the same task, each one more efficient
than the previous example. Both utilize the shortcut object reference to get at the
heart of the text object. Listing 25-3 passes the text object — contained in the this
reference — to the function handler. Because that text object contains a complete
reference to it (out of sight, but there just the same), you can access the value
property of that object and assign a string to that object’s value property in a simple
assignment statement.
Listing 25-3: Passing a Text Object (as this) to the Function
Text Object Value
function upperMe(field) {
field.value = field.value.toUpperCase()
}
Enter lowercase letters for conversion to uppercase:
Yet another way is to deal with the field values directly in an embedded event
handler — instead of calling an external function (which is easier to maintain
because all scripts are grouped together in the Head). With the function removed
from the document, the event handler attribute of the tag changes to do
all the work:
document.formObject.textObject.value