// ************************
// layer utility routines *
// ************************

function getStyleObject(objectId) {
    // cross-browser function to get an object's style object given its id
    if(document.getElementById && document.getElementById(objectId)) {
	// W3C DOM
	return document.getElementById(objectId).style;
    } else if (document.all && document.all(objectId)) {
	// MSIE 4 DOM
	return document.all(objectId).style;
    } else if (document.layers && document.layers[objectId]) {
	// NN 4 DOM.. note: this won't find nested layers
	return document.layers[objectId];
    } else {
	return false;
    }
} // getStyleObject

function changeObjectVisibility(objectId, newVisibility) {
    // get a reference to the cross-browser style object and make sure the object exists
    var styleObject = getStyleObject(objectId);
    if(styleObject) {
	styleObject.visibility = newVisibility;
	return true;
    } else {
	// we couldn't find the object, so we can't change its visibility
	return false;
    }
} // changeObjectVisibility


function changeDisplay( elementId, setTo ) {
	/*	setTo can be 'block', 'none', or '' (for default)
		onclick="changeDisplay( 'aUniqueId', 'block' );"
	*/
    if( document.getElementById ) {
        //DOM
        var theElement = document.getElementById( elementId );
    } else {
        if( document.all ) {
            //Proprietary DOM
            var theElement = document.all[ elementId ];
        } else {
            //Create an object to prevent errors further on
            var theElement = new Object();
        }
    }
    if( !theElement ) {
        /* The page has not loaded or the browser claims to support
        document.getElementById or document.all but cannot actually
        use either */
        return;
    }
    //Reference the style ...
    if( theElement.style ) { theElement = theElement.style; }
    if( typeof( theElement.display ) == 'undefined' &&
    !( window.ScriptEngine && ScriptEngine().indexOf('InScript') + 1 ) ) {
      //The browser does not allow us to change the display style
      return;
    }
    //Change the display style
    theElement.display = setTo;
}


function moveObject(objectId, newXCoordinate, newYCoordinate) {
    // get a reference to the cross-browser style object and make sure the object exists
    // Some older browsers do not like to have the units (px) written after the size, 
    // while Gecko in particular requires it for strict doctypes.
    var styleObject = getStyleObject(objectId);
    var noPx = document.childNodes ? 'px' : 0; 
    if(styleObject) {
		styleObject.left = newXCoordinate + noPx;
		styleObject.top = newYCoordinate + noPx;
		return true;
    } else {
		// we couldn't find the object, so we can't very well move it
		return false;
    }
} // moveObject


// **********************
// Window Size routines *
// **********************

function getWindowHeight() {
	var windowHeight = 0;
	if (typeof(window.innerHeight) == 'number') {
		windowHeight = window.innerHeight;
	}
	else {
		if (document.documentElement && document.documentElement.clientHeight) {
			windowHeight = document.documentElement.clientHeight;
		}
		else {
			if (document.body && document.body.clientHeight) {
				windowHeight = document.body.clientHeight;
			}
		}
	}
	return windowHeight;
} // getWindowHeight


function getWindowWidth() {
	var windowWidth = 0;
	if (typeof(window.innerWidth) == 'number') {
		windowWidth = window.innerWidth;
	}
	else {
		if (document.documentElement && document.documentElement.clientWidth) {
			windowWidth = document.documentElement.clientWidth;
		}
		else {
			if (document.body && document.body.clientWidth) {
				windowWidth = document.body.clientWidth;
			}
		}
	}
	return windowWidth;
} // getWindowWidth


function getScrollXY() {
	var scrOfX = 0, scrOfY = 0;
	if( typeof( window.pageYOffset ) == 'number' ) {
		//Netscape compliant
		scrOfY = window.pageYOffset;
		scrOfX = window.pageXOffset;
	} else if( document.body && ( document.body.scrollLeft || document.body.scrollTop ) ) {
		//DOM compliant
		scrOfY = document.body.scrollTop;
		scrOfX = document.body.scrollLeft;
	} else if( document.documentElement && ( document.documentElement.scrollLeft || document.documentElement.scrollTop ) ) {
		//IE6 standards compliant mode
		scrOfY = document.documentElement.scrollTop;
		scrOfX = document.documentElement.scrollLeft;
	}
	return [ scrOfX, scrOfY ];
} // getScrollXY