// Global Variables
var isCSS, isW3C, isNN4, isIE6CSS;

//Initialize upon load to let all browsers establish content objects
function initDHTMLAPI() {
	if(document.images) {
		isCSS = (document.body && document.body.style) ? true : false;
		isW3C = (isCSS && document.all) ? true : false;
		isNN4 = (document.layers) ? true : false;
		isIE6CSS = (document.compatMode && document.compatMode.indexOf("CSS1") >= 0) ? true : false;
	}
}

//Set event handler to initialize API
window.onload = initDHTMLAPI;

//Seek nested NN4 layer from string name
function seekLayer(doc, name) {
	var theObj;
	for (var i = 0; i < doc.layers.length; i++) {
		if (doc.layers[i].name == name) {
			theObj = doc.layers[i];	
			break;
		}
		//dive into the nested layers if necessary
		if (doc.layers[i].document.layers.length > 0) {
			theObj = seekLayer(document.layers[i].document, name);	
		}
	}
	return theObj;
}

function getRawObject(obj) {
	var theObj;
	if(typeof obj == "string") {
		if(isW3C) {
			theObj = document.getElementById(obj);
		} else if(isIE4) {
			theObj = document.all(obj);
		} else if (isNN4) {
			theObj = seekLayer(document, obj);
		}
	} else {
		theObj = obj;
	}
	return theObj;
}

//Convert object name string or object reference into a valid style or reference
function getObject(obj) {
	//alert("getObject was fired");
	var theObj = getRawObject(obj);
	if (theObj && isCSS) {
		theObj = theObj.style;
	}
	return theObj;
}

//Position an object at a specific pixel coordinate
function shiftTo(obj, x, y) {
	var theObj = getObject(obj);
	if (theObj) {
		if (isCSS) {
			//equalize incorrect numeric value type
			var units = (typeof theObj.left == "string") ? "px" : 0;
			theObj.left = x + units;
			theObj.top = y + units;
		} else if (isNN4) {
			theObj.moveTo(x,y)
		}
	}
}

//Move an object  by x and/or y pixels
function shiftBy(obj, deltaX, deltaY) {
	var theObj = getObject(obj);
	if (theObj) {
		if (isCSS) {
			//equalize incorrect numeric value type
			var units = (typeof theObj.left == "string") ? "px" : 0;
			//alert(getObjectLeft(obj));
			theObj.left = getObjectLeft(obj) + deltaX + units;
			theObj.top = getObjectTop(obj) + deltaY + units;
		} else if (isNN4) {
			theObj.moveTo(x,y);
		}
	}
	//alert("shiftBy is finished");
}

//Set the z-order of an object
function setZIndex(obj, zOrder) {
	var theObj = getObject(obj);
	if (theObj) {
		theObj.zIndex = zOrder;
	}
}

//Set the background color of an object
function setBGColor(obj, color) {
	var theObj = getObject(obj);
	if (theObj) {
		if (isNN4) {
			theObj.bgColor = color;
		} else if (isCSS) {
			theObj.backgroundColor = color;
		}
	}
}

//Set the visibility of an object to visible
function show(obj) {
	var theObj = getObject(obj);
	if (theObj) {
		theObj.visibility = "visible";
	}
}

//Set the visibility of an object to hidden
function hide(obj) {
	var theObj = getObject(obj);
	if (theObj) {
		theObj.visibility = "hidden";
	}
}

//Retrieve the x coordinate of a positionable object
function getObjectLeft(obj) {
	//alert("getObjectLeft is running");
	var elem = getRawObject(obj);
	var result = 0;
	if (document.defaultView) {
		var style = document.defaultView;
		var cssDecl = style.getComputedStyle(elem, "");
		result = cssDecl.getPropertyValue("left");
	} else if (elem.currentStyle) {
		result = elem.currentStyle.left;
	} else if (elem.style) {
		result = elem.style.left;
	} else if (isNN4) {
		result = elem.left;
	}
	return parseInt(result);
}

//Retrieve the y coordinate of a positionable object
function getObjectTop(obj) {
	var elem = getRawObject(obj);
	var result = 0;
	if (document.defaultView) {
		var style = document.defaultView;
		var cssDecl = style.getComputedStyle(elem, "");
		result = cssDecl.getPropertyValue("top")
	} else if (elem.currentStyle) {
		result = elem.currentStyle.top;
	} else if(elem.style){
		result = elem.style.top;
	} else if (isNN4) {
		result = elem.top;
	}
	alert(result);
	return parseInt(result);
}

//Retirieve the rendered width of an element
function getObjectWidth(obj) {
	var elem = gatRawObject(obj);
	var result = 0;
	if (elem.offsetWidth) {
		result = elem.offsetWidth;	
	} else if (elem.clip && elem.clip.width) {
		result = elem.clip.width;
	} else if (elem.style && elem.style.pixelWidth) {
		result = elem.style.pixelWidth;
	}
	return parseInt(result);
}

//Retrieve the rendered height of an element
function getObjectHeight(obj) {
	var elem = getRawObject(obj);
	var result = 0;
	if (elem.offsetHeight) {
		result = elem.offsetHeight;
	} else if (elem.clip && elem.clip.height) {
		result = elem.clip.height;
	} else if (elem.style && elem.style.pixelHeight) {
		result = elem.style.pixelHeight;
	}
	return parseInt(result);
}

//Return the available content width space in browser window
function getInsideWindowWidth() {
	if (window.innerWidth) {
		return window.innerWidth;
	} else if (isIE6CSS) {
		//Measure the html element's clentwidth
		return document.body.parentElement.clientWidth;
	} else if (document.body && document.body.clientHeight) {
		return document.bodyclientHeight;
	}
	return 0;
}