One of the issues of document object model (DOM) is: Sometimes you have to get you request.
Object is just pain. For example, there is a function to ask the user to transform
Which image: Which image is transformed?
You can use the following functions:
Function swapone ()
{
VAR THE_IMAGE = Prompt ("Change Parrot or Cheese", ""
Var the_image_object;
IF (THE_IMAGE == "Parrot")
{
THE_IMAGE_Object = Window.Document.Parrot;
}
Else {
THE_IMAGE_OBJECT = WINDOW.Document.chese;
}
THE_IMAGE_Object.src = "Ant.gif";
}
Contains along with these image tags:
Please pay attention to a few line of statement like this:
THE_IMAGE_Object = Window.Document.Parrot;
It applies a parrot image object to a variable. Although it looks a bit
The child is strange, it has no problem in grammar. But when you have 100 instead of two
What should I do when the image? You have to write a big pile of if-thein-else statement, if
It's better to like this:
Function swaptwo ()
{
VAR THE_IMAGE = Prompt ("Change Parrot or Cheese", ""
Window.Document.The_Image.src = "Ant.gif";
}
Unfortunately, JavaScript will look for the name called THE_IMAGE instead of you.
The image of "Cheese" or "Parrot", so you got an error message: "
Haven't heard a object called the_image. "
Fortunately, Eval can help you get the object you want.
Function SimpleSwap ()
{
VAR THE_IMAGE = Prompt ("Change Parrot or Cheese", ""
VAR THE_IMAGE_NAME = "Window.Document." the_image;
VAR THE_IMAGE_OBJECT = EVAL (THE_IMAGE_NAME);
THE_IMAGE_Object.src = "Ant.gif";
}
If the user fills in "Parrot" in the prompt box, a word is created in the second line.
The string is Window.Document.Parrot. Then contain the third of Eval
Executive is: "Give me object window.document.parrot" - That is
The image object you want. Once you get this image object, you can put
Its SRC property is set to Ant.gif. Is it a little scared? Not. In fact, this is quite
Using, people often use it.
