var isAll=(document.all) ? true : false;
var isLay=(document.layers) ? true : false;
var isbyId=(document.getElementById && !document.all) ? true : false;


function returnDomElement(ref){
	if(ref && isObject(ref)){
		return ref;
	}else{
		if(isAll){
			if(document.all[ref]){
				return document.all[ref];
			}else{
				return false;
			}
		}else if(isLay){
			if(document.layers[ref]){
				return document.layers[ref];
			}else{
				return false;
			}
		}else if(isbyId){
			if(document.getElementById([ref])){
				return document.getElementById([ref]);
			}else{
				return false;
			}
		}
	}
}

function addToFavourites(){
	if(window.external){
		window.external.AddFavorite(location.href,document.title)
	}else{
		alert("Windows, Netscape users: Ctrl + D")
	}
}

function hideLayer(ref){
	var oLayerRef=returnDomElement(ref)
	if(isAll && oLayerRef){
		oLayerRef.style.visibility='hidden';
	}
	if(isLay && oLayerRef){
		oLayerRef.visibility='hide';
	}
	if(isbyId && oLayerRef){
		oLayerRef.style.display='none';
	}
	return false;
}


function showLayer(ref){
	var oLayerRef=returnDomElement(ref)
	if(isAll && oLayerRef){
		oLayerRef.style.visibility='visible';
	}
	if(isLay && oLayerRef){
		oLayerRef.visibility='show';
	}
	if(isbyId && oLayerRef){
		oLayerRef.style.display='block';
	}
	return false;
}


function writeToLayer(ref,sTxt){
	var oLayerRef=returnDomElement(ref)
	if(isAll && oLayerRef){
		oLayerRef.innerHTML=sTxt;
	}
	if(isLay && oLayerRef){
		oLayerRef.document.write(sTxt);
		oLayerRef.document.close();
	}
	if(isbyId && oLayerRef){
		var oRange=document.createRange();
		var oDomFrag=oRange.createContextualFragment(sTxt);
		oRange.setStartBefore(oLayerRef);
		while (oLayerRef.hasChildNodes()){
			oLayerRef.removeChild(oLayerRef.lastChild);
		}
		oLayerRef.appendChild(oDomFrag);
  	}
	return false;
}


function selectTextRange(ref){
	var oLayerRef=returnDomElement(ref);
	if(oLayerRef.createTextRange!=null){
		var oTxtRange=oLayerRef.createTextRange();
		oTxtRange.select();
	}
	return false;
}


function clearField(ref,sDefaultValue){
	var oLayerRef=returnDomElement(ref);
	var sValue=oLayerRef.value;
	if(oLayerRef && sValue==sDefaultValue){
		oLayerRef.value="";
		selectTextRange(oLayerRef);
	}else{
		selectTextRange(oLayerRef);
	}
	return false;
}


function changeBgColour(){
	if(isLay || isAll){
		with(changeBgColour){
			// Loop through all arguments, two at a time.
			for(i=0;i<(arguments.length-1);i+=2){
				if(isLay){
					returnDomElement(arguments[i]).document.bgColor=arguments[i+1];
				}else if(isAll){
					returnDomElement(arguments[i]).style.backgroundColor=arguments[i+1];
				}
			}
		}
	}
}


/* old version, doesn't support multiple layers
function changeBgColour(ref,sHexValue){
	var sChgCell;
	var oLayerRef=returnDomElement(ref);
	if(isAll && oLayerRef){
		sChgCell="oLayerRef.style.backgroundColor='"+sHexValue+"'";
	}
	if(isLay && oLayerRef){
		sChgCell="oLayerRef.bgColor='"+sHexValue+"'";
	}
	if(isbyId && oLayerRef){
		sChgCell="oLayerRef.style.backgroundColor='"+sHexValue+"'";
  	}
	eval(sChgCell);
	return false;
}
*/


function autoFormFocus(nForm){
	if(!nForm){
		nForm=0;
	}
	if(document.forms[nForm]){
		var nCount;
		var aFormElements=document.forms[nForm].elements;
		aFormElements[nForm].focus();
	}else{
		return false;
	}
}


function swapImage(ref,sSrc){
	var oLayerRef=returnDomElement(ref);
	if(oLayerRef){
		oLayerRef.src=sSrc;
	}
	return false;
}


function urlEncode(sString){
	return escape(sString);
}


function urlDecode(sString){
	return unescape(sString);
}


function isArray(a){
    return isObject(a) && a.constructor==Array;
}


function isBoolean(a){
    return typeof a=='boolean';
}


function isEmpty(o){
    var i,v;
    if (isObject(o)){
        for (i in o){
            v=o[i];
            if (isUndefined(v) && isFunction(v)){
                return false;
            }
        }
    }
    return true;
}


function isFunction(a){
    return typeof a=='function';
}


function isNull(a){
    return typeof a=='object' && !a;
}


function isNumber(a){
    return typeof a=='number' && isFinite(a);
}


function isObject(a){
    return (a && typeof a=='object') || isFunction(a);
}


function isString(a){
    return typeof a=='string';
}


function isUndefined(a){
    return typeof a=='undefined';
}