var backgr1="/images/1.jpg"
    var backgr2="/images/3.jpg"
    var backgr3="/images/5.jpg"
    var backgr4="/images/6.jpg"
    var backgr5="/images/7.jpg"
    var backgr6="/images/8.jpg"
    var backgr7="/images/9.jpg"
    var backgr8="/images/10.jpg"

    var cur = Math.floor(Math.random() * 8) + 1;

    if (cur==1)
        backgr=backgr1
       else if (cur==2)
        backgr = backgr2
      else if (cur==3)
        backgr = backgr3
    else if (cur==4)
        backgr = backgr4
    else if (cur==5)
        backgr = backgr5
    else if (cur==6)
        backgr = backgr6
    else if (cur==7)
        backgr = backgr7
    else if (cur==8)
        backgr = backgr8
  

    document.write('<img src="' + backgr + '" alt="" style="position: fixed; top: 0; left: 0; width: 100%; height: 100%;">');