// Copyright © 2000 by Apple Computer, Inc., All Rights Reserved.
//
// You may incorporate this Apple sample code into your own code
// without restriction. This Apple sample code has been provided "AS IS"
// and the responsibility for its operation is yours. You may redistribute
// this code, but you are not permitted to redistribute it as
// "Apple sample code" after having made changes.
//
// ************************
// 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 moveObject(objectId, newXCoordinate, newYCoordinate) { 
    // get a reference to the cross-browser style object and make sure the object exists
    var styleObject = getStyleObject(objectId);
    if(styleObject) {
      if( navigator.platform.indexOf("Mac") == -1 ) {
    	  styleObject.left = newXCoordinate;
    	  styleObject.top = newYCoordinate;
    	}
    	return true;
    } else {
	    // we couldn't find the object, so we can't very well move it
	    return false;
    }
} // moveObject