if (document.images) {
var button_1a=new Image();
button_1a.src="/images/main/button_1a.jpg";
var button_1b=new Image();
button_1b.src="/images/main/button_1b.jpg";
var button_2a=new Image();
button_2a.src="/images/main/button_2a.jpg";
var button_2b=new Image();
button_2b.src="/images/main/button_2b.jpg";
var button_3a=new Image();
button_3a.src="/images/main/button_3a.jpg";
var button_3b=new Image();
button_3b.src="/images/main/button_3b.jpg";
var button_4a=new Image();
button_4a.src="/images/main/button_4a.jpg";
var button_4b=new Image();
button_4b.src="/images/main/button_4b.jpg";
}
else {
alert("Helaas, u heeft een te oude browser.");
}