var pic_wbanner = new Array();

pic_wbanner[0] = "fileadmin/site/wbanner/web1.jpg";
pic_wbanner[1] = "fileadmin/site/wbanner/web2.jpg";
pic_wbanner[2] = "fileadmin/site/wbanner/web3.jpg";
pic_wbanner[3] = "fileadmin/site/wbanner/web4.jpg";
pic_wbanner[4] = "fileadmin/site/wbanner/web5.jpg";

var arraylaenge_wbanner = pic_wbanner.length;
var index_wbanner = Math.floor(Math.random() * arraylaenge_wbanner);
var Pic = '<img src="' + pic_wbanner[index] + '">';

function change_pic () {
if (index_wbanner == arraylaenge_wbanner-1) {
index_wbanner = 0;
} else {
index_wbanner++;
}
Picstring ='<img src="' + pic_wbanner[index_wbanner] + '" class="wpic">';
document.getElementById('wbanner').innerHTML = Picstring;
}

function Showpic () {
document.getElementById('wbanner').innerHTML = Picstring;
change_pic();
}