var imagenumber = 4 ;
var randomnumber = Math.random() ;
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ;
var erhverv = "../billederrand/erhverv_" + rand1 + ".jpg"

var imagenumber = 6 ;
var randomnumber = Math.random() ;
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ;
var it = "../billederrand/it_" + rand1 + ".jpg"

var imagenumber = 10 ;
var randomnumber = Math.random() ;
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ;
var omia = "../billederrand/omia_" + rand1 + ".jpg"

var imagenumber = 30 ;
var randomnumber = Math.random() ;
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ;
var underv = "../billederrand/underv_" + rand1 + ".jpg"