// DHTMLapi.js custom API for cross-platform
// object positioning by Danny Goodman (http://www.dannyg.com)
// Modified by Mark Royer (mroyer@cs.usm.maine.edu)
// Release 2.0 Supports NN4, IE, and W3C DOMS.

// Global variables
var isCSS, isW3C, isIE4, isNN4, isIE6CSS;


// Refreshes the screen
function refresh(){
    if ((isIE4 || isIE6CSS) && 
	(navigator.appName == "Microsoft Internet Explorer"))
 	location.reload();	
}


// 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.getElementById) ? true : false;
        isIE4 = (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 nested layers if necessary
        if (doc.layers[i].document.layers.length > 0){
            theObj = seekLayer(document.layers[i].document, name);
        }
    }

    return theObj;
}


// Convert object name string or object reference
// into a valid element object reference
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 {
        // pass through object reference
        theObj = obj;
    }

    return theObj;
}


// Convert object name string or object reference
// into a valid style (or NN4 layer) reference
function getObject(obj){
    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 inicorrect numeric value type
            var units = (typeof theObj.left == "string") ? "px" : 0;
            theObj.left = getObjectLeft(obj) + deltaX + units;
            theObj.top = getObjectTop(obj) + deltaY + units;
        } else if (isNN4){
            theObj.moveBy(deltaX, deltaY);
        }
    }
}


// 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){
    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;
    }

    return parseInt(result);
}


// Retrieve the rendered width of an element
function getObjectWidth(obj) {
    var elem = getRawObject(obj);
 
    var result = 0;

    if (elem.offsetWidth){
        if (elem.scrollWidth && (elem.offsetWidth != elem.scrollWidth) && 
            navigator.appName != "Microsoft Internet Explorer"){
            result = elem.scrollWidth;
        } else {
            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.syle && 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 clientWidth
        return document.body.parentElement.clientWidth;
    } else if (document.body && document.body.clientWidth){
        return document.body.clientWidth;
    }

    return 0;
}


// Return the available content height space in browser window
function getInsideWindowHeight(){

    if (window.innerHeight){
        return window.innerHeight;
    } else if (isIE6CSS){
        // measure the html element's clientHeight
        return document.body.parentElement.clientHeight;
    } else if (document.body && document.body.clientHeight){
	return document.body.clientHeight;        
    }

    return 0;
}

// Returns the amount the page has scrolled
function getPageYOffset()
{
    if (window.innerHeight) // netscape
	return pageYOffset;
    else if (isIE6CSS)
	return document.documentElement.scrollTop;
    else
	return document.body.scrollTop; // exlporer

    
}