// Set event handler to initialize API
var isCSS, isW3C, isIE4, isIE6CSS, isIE7, isNN4, isNN6, isOPE; 
var widthWindow, heightWindow,  minWidth, minHeight, visibleWidth, imgposition;

window.onresize = checkIBrowser;

// let all IBrowsers establish content objects
function checkIBrowser() {

	if (document.images) {
  	isCSS = (document.body && document.body.style) ? true : false;
    isW3C = (isCSS && document.getElementById) ? true : false;

    isIE4 = (isCSS && document.all) ? true : false;
    isIE6CSS = (document.compatMode && document.compatMode.indexOf("CSS1") >= 0) ? true : false;
    isIE7 = (window.XMLHttpRequest && window.ActiveXObject) ? true : false;
    isNN4 = (document.layers) ? true : false;
    isNN6 = (document.getElementById && !document.all) ? true : false;
    isOPE = (window.opera) ? true : false;
                
    if (isW3C) {   	
		 	widthWindow = getInsideWindowWidth();
		 	heightWindow = getInsideWindowHeight();
		 	
			if ( getRawObject("divextra")) {

				if (widthWindow > 760) {

					minWidth = getObjectWidth("mainbody");		 	
		 			
		 			if (getObjectHeight("divpagemenu") > getObjectHeight("divpagecontent")) {
		 				minHeight = getObjectHeight("divpagemenu");
		 				diffY = 1; 
		 			}
		 			else {
		 				minHeight = getObjectHeight("divpagecontent");		    	
		 				diffY = 0;
		 			}
		 					    	
		    	if (widthWindow > minWidth) diffX = widthWindow - minWidth;
		    	else diffX = 0;
		    	
		    	/*if (heightWindow > minHeight) diffY = 0;
		    	else diffY = -(minHeight - heightWindow);*/
		    				 			    	
		    	visibleWidth = ((widthWindow - diffX - 760)/2) & 65535;
		    	imgposition = visibleWidth - 220;
		    	shiftTo("divextra", 0, 0);
 					 
 					getObject("divextra").width = (visibleWidth < 760) ? visibleWidth + "px" : "0px";
		    	/*getObject("divextra").height =  heightWindow - diffY + 'px';*/
		    	if (heightWindow < minHeight) {		    		
		    			if ( isNN4 || isNN6 || isOPE) {
		    				getObject("divextra").height =  minHeight + 'px';
		    				if (diffY == 1) getObject("divpagecontent").height =  minHeight + 'px';
		    			}	else {
		    				getObject("divextra").height = (minHeight+13) + 'px';
		    			}
		    	}
		    	else {		    			    		  		    		
		    		getObject("divextra").height =  heightWindow + 'px';		    			    		  
		    		getObject("divpagecontent").height =  heightWindow + 'px';
		    	}		    	
		    	getObject("divextra").top = 160 + 'px';
		    	getObject("divextra").background = '#10100C url(../images/parrocchia/extra.jpg) no-repeat ' + imgposition + 'px 0';		    			 		  		    	
		    }
		    else {
		    	getObject("divextra").width = '0px';
		    	getObject("divextra").top = '-10000px';
		    }
		  }		  
    }                
    return true;    
	}  
  else return false;
}

// 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;
        }
    }
}

// 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;
}

// 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;
}

// Set the visibility of an object to visible - true or hidden - false
function showHideObject(obj, sw) {
    var theObj = getObject(obj);
    if (theObj) {
    	if (sw)
        	theObj.visibility = "visible";
        else
        	theObj.visibility = "hidden";
    }
}

// change cursor style
function cursorStyle(obj) {
	if (isCSS) {
		if (isNN4 || isNN6)
			obj.style.cursor='pointer';
		else
			obj.style.cursor='hand';
	}
	return;
}

// change all select color list for IE
function chngSelectColor() {
    var arg = chngSelectColor.arguments;
    for (i = 0; i < arg.length; i++) {
        obj = getRawObject(arg[i]);
        if (obj) {
			for (j = 0; j < obj.options.length; j++) {
			    if (obj.options[j].selected == false) {
				    chngInputColor(obj.options[j], true, true);
			    }
			}
        }
    }
}

// change Input Color
function chngInputColor(what, sw, init, colorSelected, colorNotSelected) {
	if (sw) { // on focus
		setBGColor(what, colorSelected);
		if (!init) {
			objElement = getRawObject(what.name);
			if (objElement.options)
				for (i = 0; i < objElement.options.length; i++)
					setBGColor(objElement.options[i], colorSelected);
		}
	}
	else { // on blur
		setBGColor(what, colorNotSelected);
		objElement = getRawObject(what.name);
		if (objElement.options)
			setBGColor(objElement.options[objElement.selectedIndex], colorNotSelected);
	}

}

// 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 
            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;
    }
}

// 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) {
        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 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;
}