button1_a= new Image();
button1_a.src = "images/agentur_off.png"
button1_b= new Image();
button1_b.src = "images/agentur_on.png"
button2_a= new Image();
button2_a.src = "images/leistungen_off.png"
button2_b= new Image();
button2_b.src = "images/leistungen_on.png"
button3_a= new Image();
button3_a.src = "images/service_off.png"
button3_b= new Image();
button3_b.src = "images/service_on.png"
button4_a= new Image();
button4_a.src = "images/kontakt_off.png"
button4_b= new Image();
button4_b.src = "images/kontakt_on.png"