function checkemail(email)
{
// a very simple email validation checking. 
// you can add more complex email checking if it helps 
    if(email.length <= 0)
	{
	  return true;
	}
    var splitted = email.match("^(.+)@(.+)$");
    if(splitted == null) return false;
    if(splitted[1] != null )
    {
      var regexp_user=/^\"?[\w-_\.]*\"?$/;
      if(splitted[1].match(regexp_user) == null) return false;
    }
    if(splitted[2] != null)
    {
      var regexp_domain=/^[\w-\.]*\.[A-Za-z]{2,4}$/;
      if(splitted[2].match(regexp_domain) == null) 
      {
	    var regexp_ip =/^\[\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\]$/;
	    if(splitted[2].match(regexp_ip) == null) return false;
      }// if
      return true;
    }
return false;
}

function datacheck(objValue,strValidateStr,strError) 
{ 
    var epos = strValidateStr.search("="); 
    var  command  = ""; 
    var  cmdvalue = ""; 
    if(epos >= 0) 
    { 
     command  = strValidateStr.substring(0,epos); 
     cmdvalue = strValidateStr.substr(epos+1); 
    } 
    else 
    { 
     command = strValidateStr; 
    } 
    switch(command) 
    { 
        case "req": 
        case "required": 
         { 
           if(eval(objValue.length) == 0) 
           { 
              if(!strError || strError.length ==0) 
              { 
                strError = " Required Field"; 
              }//if 
              alert(strError); 
              return false; 
           }//if
		               
         }//case required 
		 
        case "maxlength": 
        case "maxlen": 
          { 
             if(eval(objValue.length) >  eval(cmdvalue)) 
             { 
               if(!strError || strError.length ==0) 
               { 
                 strError = cmdvalue+" characters maximum "; 
               }//if 
               alert(strError + "\n[Current length = " + objValue.length + " ]"); 
               return false; 
             }//if 
             break; 
          }//case maxlen 
        case "minlength": 
        case "minlen": 
           { 
             if(eval(objValue.length) <  eval(cmdvalue)) 
             { 
               if(!strError || strError.length ==0) 
               { 
                 strError = " : " + cmdvalue + " characters minimum  "; 
               }//if               
               alert(strError + "\n[Current length = " + objValue.length + " ]"); 
               return false;                 
             }//if 
             break; 
            }//case minlen 
        case "alnum": 
        case "alphanumeric": 
           { 
              var charpos = objValue.search("[^A-Za-z0-9]"); 
              if(objValue.length > 0 &&  charpos >= 0) 
              { 
               if(!strError || strError.length ==0) 
                { 
                  strError = ": Only alpha-numeric characters allowed "; 
                }//if 
                alert(strError + "\n [Error character position " + eval(charpos+1)+"]"); 
                return false; 
              }//if 
              break; 
           }//case alphanumeric 
        case "num": 
        case "numeric": 
           { 
              var charpos = objValue.search("[^0-9]"); 
              if(objValue.length > 0 &&  charpos >= 0) 
              { 
                if(!strError || strError.length ==0) 
                { 
                  strError = ": Only digits allowed "; 
                }//if               
                alert(strError + "\n [Error character position " + eval(charpos+1)+"]"); 
                return false; 
              }//if 
              break;               
           }//numeric 
		  case "float": 

           { 
              var charpos = objValue.search("[^0-9.]"); 
              if(objValue.length > 0 &&  charpos >= 0) 
              { 
                if(!strError || strError.length ==0) 
                { 
                  strError = ": Only digits allowed "; 
                }//if               
                alert(strError + "\n [Error character position " + eval(charpos+1)+"]"); 
                return false; 
              }//if 
              break;               
           }//decimal point 
        case "alphabetic": 
        case "alpha": 
           { 
              var charpos = objValue.search("[^A-Za-z]"); 
              if(objValue.length > 0 &&  charpos >= 0) 
              { 
                  if(!strError || strError.length ==0) 
                { 
                  strError = ": Only alphabetic characters allowed "; 
                }//if                             
                alert(strError + "\n [Error character position " + eval(charpos+1)+"]"); 
                return false; 
              }//if 
              break; 
           }//alpha 
		case "alnumhyphen":
			{
              var charpos = objValue.search("[^A-Za-z0-9\-_]"); 
              if(objValue.length > 0 &&  charpos >= 0) 
              { 
                  if(!strError || strError.length ==0) 
                { 
                  strError = ": characters allowed are A-Z,a-z,0-9,- and _"; 
                }//if                             
                alert(strError + "\n [Error character position " + eval(charpos+1)+"]"); 
                return false; 
              }//if 			
			break;
			}
        case "email": 
          { 
               if(!checkemail(objValue)) 
               { 
                 if(!strError || strError.length ==0) 
                 { 
                    strError = ": Enter a valid Email address "; 
                 }//if                                               
                 alert(strError); 
                 return false; 
               }//if 
           break; 
          }//case email 
        case "lt": 
        case "lessthan": 
         { 
            if(isNaN(objValue)) 
            { 
              alert(objValue.name+": Should be a number "); 
              return false; 
            }//if 
            if(eval(objValue) >=  eval(cmdvalue)) 
            { 
              if(!strError || strError.length ==0) 
              { 
                strError = " : value should be less than "+ cmdvalue; 
              }//if               
              alert(strError); 
              return false;                 
             }//if             
            break; 
         }//case lessthan 
        case "gt": 
        case "greaterthan": 
         { 
            if(isNaN(objValue)) 
            { 
              alert(": Should be a number "); 
              return false; 
            }//if 
             if(eval(objValue) <=  eval(cmdvalue)) 
             { 
               if(!strError || strError.length ==0) 
               { 
                 strError = " : value should be greater than "+ cmdvalue; 
               }//if               
               alert(strError); 
               return false;                 
             }//if             
            break; 
         }//case greaterthan 
       
        
		
    }//switch 
    return true; 
}