JavaScript to get the browser body height and width

Definition criteria
IE:
Document. Body. clientwidth ==> body object width
Document. Body. clientheight ==> body object height
Document.doc umentelement. clientwidth ==> visible area width
Document.doc umentelement. clientheight => visible area height

Firefox:
Document. Body. clientwidth ==> body object width
Document. Body. clientheight ==> body object height
Document.doc umentelement. clientwidth ==> visible area width
Document.doc umentelement. clientheight => visible area height

Opera:
Document. Body. clientwidth ==> visible area width
Document. Body. clientheight ==> visible area height

The following is more practical:
Document.doc umentelement. clientwidth ==> Page Object width (that is, the width of the body object plus the margin width)
Document.doc umentelement. clientheight ==> Page Object height (that is, the height of the body object plus the margin height)

Undefined Standard
IE:
Document.doc umentelement. clientwidth ==> 0
Document.doc umentelement. clientheight => 0

Firefox:
Document.doc umentelement. clientwidth ==> Page Object width (that is, the width of the body object plus the margin width)
Document.doc umentelement. clientheight ==> Page Object height (that is, the height of the body object plus the margin height)

Opera:
document.doc umentelement. clientwidth ==> Page Object width (that is, the width of the body object plus the margin width)
document.doc umentelement. clientheight ==> Page Object height (that is, the height of the body object plus the margin height)