Quirks mode and Standards mode return value is inconsistent. Since you tagged it as jQuery, just use
$('body').height()
or $(window).height()
depending on what you need... it fixes it internally so you don't have to type this:
jQuery.each([ "Height", "Width" ], function( i, name ) {
var type = name.toLowerCase();
// innerHeight and innerWidth
jQuery.fn["inner" + name] = function() {
return this[0] ?
jQuery.css( this[0], type, false, "padding" ) :
null;
};
// outerHeight and outerWidth
jQuery.fn["outer" + name] = function( margin ) {
return this[0] ?
jQuery.css( this[0], type, false, margin ? "margin" : "border" ) :
null;
};
jQuery.fn[ type ] = function( size ) {
// Get window width or height
var elem = this[0];
if ( !elem ) {
return size == null ? null : this;
}
if ( jQuery.isFunction( size ) ) {
return this.each(function( i ) {
var self = jQuery( this );
self[ type ]( size.call( this, i, self[ type ]() ) );
});
}
return ("scrollTo" in elem && elem.document) ? // does it walk and quack like a window?
// Everyone else use document.documentElement or document.body depending on Quirks vs Standards mode
elem.document.compatMode === "CSS1Compat" && elem.document.documentElement[ "client" + name ] ||
elem.document.body[ "client" + name ] :
// Get document width or height
(elem.nodeType === 9) ? // is it a document
// Either scroll[Width/Height] or offset[Width/Height], whichever is greater
Math.max(
elem.documentElement["client" + name],
elem.body["scroll" + name], elem.documentElement["scroll" + name],
elem.body["offset" + name], elem.documentElement["offset" + name]
) :
// Get or set width or height on the element
size === undefined ?
// Get width or height on the element
jQuery.css( elem, type ) :
// Set the width or height on the element (default to pixels if value is unitless)
this.css( type, typeof size === "string" ? size : size + "px" );
};
});