// Bilderwechsel und Preload



var bildPfad = 'img/'

	buttonOn = new Array();

	buttonOff = new Array();



function preloadImages(){

	 if (document.images){

		 for (i =0; i<document.images.length;i++){



				if (document.images[i].name.indexOf('_button')!=-1){



						stopPoint = document.images[i].name.indexOf('_button');

						bildName=document.images[i].name.substring(0,stopPoint);



						buttonOn[document.images[i].name] = new Image();

						buttonOn[document.images[i].name].src = bildPfad + bildName + '_on.gif';



						buttonOff[document.images[i].name] = new Image();

						buttonOff[document.images[i].name].src = bildPfad + bildName + '_off.gif';



					}



				}

				if (selectedArea) lightUp(selectedArea);

			}

	}



function lightUp(which){



		if (document.images){



			whichButton = which +"_button"

			newButton =  buttonOn[whichButton]

			if(buttonOn[whichButton]) document.images[whichButton].src=buttonOn[whichButton].src;



			return true;

			}

		}



function darken(which){



	if ((document.images)&&(selectedArea!=(which + '_button'))){



		whichButton = which +"_button"

		newButton = buttonOff[whichButton]

		if(buttonOff[whichButton]) document.images[whichButton].src=buttonOff[whichButton].src;





		return true;

	}



}



var selectedArea=''; // Button, der markiert bleiben soll