function init(){


 button1 = new button(1, "http://www.reusch.com/site/images/start_s_1off.gif", "http://www.reusch.com/site/images/start_s_1on.gif");
 button2 = new button(2, "http://www.reusch.com/site/images/start_s_2off.gif", "http://www.reusch.com/site/images/start_s_2on.gif");
 button3 = new button(3, "http://www.reusch.com/site/images/start_s_3off.gif", "http://www.reusch.com/site/images/start_s_3on.gif");
 button4 = new button(4, "http://www.reusch.com/site/images/start_s_4off.gif", "http://www.reusch.com/site/images/start_s_4on.gif");
 button5 = new button(5, "http://www.reusch.com/site/images/start_s_5off.gif", "http://www.reusch.com/site/images/start_s_5on.gif");
 button6 = new button(6, "http://www.reusch.com/site/images/start_s_6off.gif", "http://www.reusch.com/site/images/start_s_6on.gif");
 button7 = new button(7, "http://www.reusch.com/site/images/start_s_7off.gif", "http://www.reusch.com/site/images/start_s_7on.gif");
 //button problem lösung!
 // document.getElementById("menu").style.visibility="visible";
 
 }
 
function button(id, src_off, src_on){
 this.id = id;
 
 this.image_off = new Image();
 this.image_off.src = src_off;
 this.image_on = new Image();
 this.image_on.src = src_on;
 
 
 //methoden
 this.show_on = show_on;
 this.show_off = show_off; 
}
 
//methoden des button objects
function show_on(){
 document.images['button_' + this.id].src = this.image_on.src;
}
 
function show_off(){
 document.images['button_' + this.id].src = this.image_off.src;
}