var t1 = 60 // interval in seconds
imgsrc1 = "";
LoadImg1();

function LoadImg1() {
if (imgsrc1 == "") imgsrc1 = document.getElementById('webcam01').src;
tmp = new Date();
tmp = "?"+tmp.getTime();
document.getElementById("webcam01").src = imgsrc1+tmp;
setTimeout("LoadImg1()", t1*1000);
}