var ns4;
var op5;
var op6;
var agt;
var mac;
var ie; 
var mac_ie;

function sniffBrowsers() {
	ns4 = document.layers;
	op5 = (navigator.userAgent.indexOf("Opera 5")!=-1) ||(navigator.userAgent.indexOf("Opera/5")!=-1);
	op6 = (navigator.userAgent.indexOf("Opera 6")!=-1) ||(navigator.userAgent.indexOf("Opera/6")!=-1);
	agt=navigator.userAgent.toLowerCase();
	mac = (agt.indexOf("mac")!=-1);
	ie = (agt.indexOf("msie") != -1); 
	mac_ie = mac && ie;
}


function getStyleObject(objectId, doc) {
    if(document.getElementById && document.getElementById(objectId)) {
	return document.getElementById(objectId).style;
    } else if (document.all && document.all(objectId)) {
	return document.all(objectId).style;
    } else if (document.layers && document.layers[objectId]) {
		return getObjNN4(document,objectId);
    } else {
	return false;
    }
} 

function changeObjectVisibility(objectId, newVisibility) {
    var styleObject = getStyleObject(objectId, document);
    if(styleObject) {
	styleObject.visibility = newVisibility;
	return true;
    } else {
	return false;
    }
} 

function findImage(name, doc) {
	var i, img;
	for (i = 0; i < doc.images.length; i++) {
    	if (doc.images[i].name == name) {
			return doc.images[i];
		}
	}
	for (i = 0; i < doc.layers.length; i++) {
    	if ((img = findImage(name, doc.layers[i].document)) != null) {
			img.container = doc.layers[i];
			return img;
    	}
	}
	return null;
}

function getImage(name) {
	if (document.layers) {
    	return findImage(name, document);
	}
	return null;
}

function getObjNN4(obj,name)
{
	var x = obj.layers;
	var foundLayer;
	for (var i=0;i<x.length;i++)
	{
		if (x[i].id == name)
		 	foundLayer = x[i];
		else if (x[i].layers.length)
			var tmp = getObjNN4(x[i],name);
		if (tmp) foundLayer = tmp;
	}
	return foundLayer;
}

function getElementHeight(Elem) {
	if (ns4) {
		var elem = getObjNN4(document, Elem);
		return elem.clip.height;
	} else {
		var elem;
		if(document.getElementById) {
			var elem = document.getElementById(Elem);
		} else if (document.all){
			var elem = document.all[Elem];
		}
		if (op5) {
			xPos = elem.style.pixelHeight;
		} else {
			xPos = elem.offsetHeight;
		}
		return xPos;
	} 
}

function getElementWidth(Elem) {
	if (ns4) {
		var elem = getObjNN4(document, Elem);
		return elem.clip.width;
	} else {
		var elem;
		if(document.getElementById) {
			var elem = document.getElementById(Elem);
		} else if (document.all){
			var elem = document.all[Elem];
		}
		if (op5) {
			xPos = elem.style.pixelWidth;
		} else {
			xPos = elem.offsetWidth;
		}
		return xPos;
	}
}

function getElementLeft(Elem) {
	if (ns4) {
		var elem = getObjNN4(document, Elem);
		return elem.pageX;
	} else {
		var elem;
		if(document.getElementById) {
			var elem = document.getElementById(Elem);
		} else if (document.all){
			var elem = document.all[Elem];
		}
		xPos = elem.offsetLeft;
		tempEl = elem.offsetParent;
  		while (tempEl != null) {
  			xPos += tempEl.offsetLeft;
	  		tempEl = tempEl.offsetParent;
  		}
		return xPos;
	}
}


function getElementTop(Elem) {
	if (ns4) {
		var elem = getObjNN4(document, Elem);
		return elem.pageY;
	} else {
		if(document.getElementById) {	
			var elem = document.getElementById(Elem);
		} else if (document.all) {
			var elem = document.all[Elem];
		}
		yPos = elem.offsetTop;
		tempEl = elem.offsetParent;
		while (tempEl != null) {
  			yPos += tempEl.offsetTop;
	  		tempEl = tempEl.offsetParent;
  		}
		return yPos;
	}
}


function getImageLeft(myImage) {
	var x, obj;
	if (document.layers) {
		var img = getImage(myImage);
    	if (img.container != null)
			return img.container.pageX + img.x;
		else
			return img.x;
  	} else {
		return getElementLeft(myImage);
	}
	return -1;
}

function getImageTop(myImage) {
	var y, obj;
	if (document.layers) {
		var img = getImage(myImage);
		if (img.container != null)
			return img.container.pageY + img.y;
		else
			return img.y;
	} else {
		return getElementTop(myImage);
	}
	return -1;
}

function getImageWidth(myImage) {
	var x, obj;
	if (document.layers) {
		var img = getImage(myImage);
		return img.width;
	} else {
		return getElementWidth(myImage);
	}
	return -1;
}



function getImageHeight(myImage) {
	var y, obj;
	if (document.layers) {
		var img = getImage(myImage);
		return img.height;
	} else {
		return getElementHeight(myImage);
	}
	return -1;
}

function moveXY(myObject, x, y) {
	obj = getStyleObject(myObject)
	if (ns4) {
		obj.top = y;
 		obj.left = x;
	} else {
		if (op5) {
			obj.pixelTop = y;
 			obj.pixelLeft = x;
		} else {
			obj.top = y + 'px';
 			obj.left = x + 'px';
		}	
	}
}

function changeClass(Elem, myClass) {
	var elem;
	if(document.getElementById) {
		var elem = document.getElementById(Elem);
	} else if (document.all){
		var elem = document.all[Elem];
	}
	if (op5 || op6) elem.style.className = myClass;
	else elem.className = myClass;
}

function changeBGColour(myObject, colour) {
	if (ns4) {
		var obj = getObjNN4(document, myObject);
		obj.bgColor=colour;
	} else {
		var obj = getStyleObject(myObject);
		if (op5) {
			obj.background = colour;	
		} else {
			obj.backgroundColor = colour;
		}	
	}
}

function changeImage(target, source) {
	var imageObj;
	
	if (ns4) {
		imageObj = getImage(target);
		if (imageObj) imageObj.src = eval(source).src; 
	} else {
		imageObj = eval('document.images.' + target);
		if (imageObj) imageObj.src = eval(source).src; 
	}
}