function checkform ( form )
{
  // see http://www.thesitewizard.com/archive/validation.shtml
  // for an explanation of this script and how to use it on your
  // own website

  // ** START **
  if (form.sub_email.value == "" || form.sub_email.value == "name@domain.com") {
    alert( "Please enter a valid email address." );
    form.sub_email.focus();
    return false ;
  }
  // ** END **
  return true ;
}
//-->

/**
* Written by Rob Schmitt, The Web Developer's Blog
* http://webdeveloper.beforeseven.com/
*/

/**
* The following variables may be adjusted
*/
var active_color = '#838383'; // Colour of user provided text
var inactive_color = '#838383'; // Colour of default text

/**
* No need to modify anything below this line
*/
window.onload = formDefaultValues;

function formDefaultValues() {
    var fields = getElementsByClassName(document, "input", "emailbox");
    if (!fields) {
        return;
    }
    var default_values = new Array();
    for (var i = 0; i < fields.length; i++) {
        fields[i].style.color = inactive_color;
        if (!default_values[fields[i].id]) {
            default_values[fields[i].id] = fields[i].value;
        }
        fields[i].onfocus = function() {
            if (this.value == default_values[this.id]) {
                this.value = '';
                this.style.color = active_color;
            }
            this.onblur = function() {
                if (this.value == '') {
                    this.style.color = inactive_color;
                    this.value = default_values[this.id];
                }
            }
        }
    }
}

/**
* getElementsByClassName()
* Written by Jonathan Snook, http://www.snook.ca/jonathan
* Add-ons by Robert Nyman, http://www.robertnyman.com
*/

function getElementsByClassName(oElm, strTagName, strClassName) {
    var arrElements = (strTagName == "*" && oElm.all) ? oElm.all : oElm.getElementsByTagName(strTagName);
    var arrReturnElements = new Array();
    strClassName = strClassName.replace(/\-/g, "\\-");
    var oRegExp = new RegExp("(^|\\s)" + strClassName + "(\\s|$)");
    var oElement;
    for (var i = 0; i < arrElements.length; i++) {
        oElement = arrElements[i];
        if (oRegExp.test(oElement.className)) {
            arrReturnElements.push(oElement);
        }
    }
    return (arrReturnElements);
}