function setMinHeight() {

    var viewportwidth;
    var viewportheight;

    // the more standards compliant browsers (mozilla/netscape/opera/IE7) use window.innerWidth and window.innerHeight

    if (typeof window.innerWidth != 'undefined') {
      viewportwidth = window.innerWidth,
      viewportheight = window.innerHeight
    }

    // IE6 in standards compliant mode (i.e. with a valid doctype as the first line in the document)

    else if (typeof document.documentElement != 'undefined'
     && typeof document.documentElement.clientWidth !=
     'undefined' && document.documentElement.clientWidth != 0) {
        viewportwidth = document.documentElement.clientWidth,
       viewportheight = document.documentElement.clientHeight
    }

    // older versions of IE

    else {
        viewportwidth = document.getElementsByTagName('body')[0].clientWidth,
        viewportheight = document.getElementsByTagName('body')[0].clientHeight
    }

    var main = document.getElementById("main");
    var footer = document.getElementById("footer");

    if (main != null && footer != null) {
       main.style.minHeight = viewportheight - footer.clientHeight + "px";
    }
}

function addClearBothDiv() {
    var main = document.getElementById("main");

    if (main != null) {
        var div = document.createElement("div");
        div.setAttribute("style", "clear: both;");
        main.appendChild(div);
    }
}

function urlencode(str) {
    var hexStr = function(dec) {
        return '%' + dec.toString(16).toUpperCase();
    };

    var ret = '',
            unreserved = /[\w.-]/; // A-Za-z0-9_.- // Tilde is not here for historical reasons; to preserve it, use rawurlencode instead
    str = (str + '').toString();

    for (var i = 0, dl = str.length; i < dl; i++) {
        var ch = str.charAt(i);
        if (unreserved.test(ch)) {
            ret += ch;
        }
        else {
            var code = str.charCodeAt(i);
            // Reserved assumed to be in UTF-8, as in PHP
            if (code === 32) {
                ret += '+'; // %20 in rawurlencode
            }
            else if (code < 128) { // 1 byte
                ret += hexStr(code);
            }
            else if (code >= 128 && code < 2048) { // 2 bytes
                ret += hexStr((code >> 6) | 0xC0);
                ret += hexStr((code & 0x3F) | 0x80);
            }
            else if (code >= 2048 && code < 65536) { // 3 bytes
                ret += hexStr((code >> 12) | 0xE0);
                ret += hexStr(((code >> 6) & 0x3F) | 0x80);
                ret += hexStr((code & 0x3F) | 0x80);
            }
            else if (code >= 65536) { // 4 bytes
                ret += hexStr((code >> 18) | 0xF0);
                ret += hexStr(((code >> 12) & 0x3F) | 0x80);
                ret += hexStr(((code >> 6) & 0x3F) | 0x80);
                ret += hexStr((code & 0x3F) | 0x80);
            }
        }
    }
    return ret;
}

function checkEmail(email) {
    var filter = /^([a-zA-Z0-9_.-])+@([a-zA-Z0-9_.-])+\.([a-zA-Z])+([a-zA-Z])+/;
    if (!filter.test(email)) {
        return false;
    } else {
        return true;
    }
    
}