function isEmail(){
		  var mail=document.getElementById('email');
		  var error='';
		  if(!mail){return false;}
		  var mailstring=mail.value;
		  if(mailstring.length==0){
		    error='Email field: You didn\'t enter a value';
		    alert(error);
		    return false;
		  }
		  if(mailstring.indexOf('@')==-1){
		    error='Email field: This email has no @ sign';
		    alert(error);
		    return false;
		  } else if(mailstring.lastIndexOf('@')!=mailstring.indexOf('@')){
		    error='Email field: An email may only contain one @ sign.';
		    alert(error);
		    return false;
		  }
		  var chunks=mailstring.split('@');
		  var n=chunks[0];
		  if(n.substring(0,1)=='.' || n.substring(0,1)=='-' || 
		      n.substr(n.length-1,1)=='.'){
		    error='Email field: The user name may not start with a period or hyphen';
		    error+=' or may not end with a period';   
		    alert(error);
		    return false;
		  }								
		  if(!checkValidCharacters(n)){
		    error='Email field: The email name contains invalid characters';
		    alert(error);
		    return false;
		  }
		  n=chunks[1];
		  if(n.substring(0,1)=='.' || n.substring(0,1)=='-' ||
		      n.substr(n.length-1,1)=='-' || n.substr(n.length-1,1)=='.'){
		    error='Email field: The domain name may not start or end with a dash or dot';
		    alert(error);
		    return false;
		  }								
		  if(!checkValidCharacters(n)){
		    error='Email field: The domain name contains invalid characters';
		    alert(error);
		    return false;
		  }
		  return true;
		}
		function checkValidCharacters(n){
		  for(var i=0;i<n.length;i++){
		    currentCode=n.charCodeAt(i);
		    if(currentCode==45 || currentCode==46 || 
			   currentCode==95 ||
			   (currentCode>96 && currentCode<123) || 
			   (currentCode>47 && currentCode<58)|| 
			   (currentCode>64 && currentCode<91)){
		     continue;
		    } else {
		     return false;
			}
		  }
		  return true;
		}