function isLogin(string) 
{
if (string.length < 5) return false;
if (!string) return false;

   var iChars = "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

   for (var i = 0; i < string.length; i++) {
      if (iChars.indexOf(string.charAt(i)) < 0)
         return false;
   }
   return true;
}             

function isDiscount(string) 
{
   var iChars = "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

   for (var i = 0; i < string.length; i++) {
      if (iChars.indexOf(string.charAt(i)) < 0)
         return false;
   }
   return true;
}     

function isName(string) 
{
if (string.length < 2) return false;
if (!string) return false;
return true;
}

function isExist(string) 
{
if (!string) return false;
return true;
}

function isEnquiry(string) 
{
if (string.length < 10) return false;
if (!string) return false;
return true;
}

function isTel(string) 
{
if (string.length < 2) return false;
if (!string) return false;
return true;
}

function isFolder(string) 
{
if (string.length < 3) return false;
if (!string) return false;

   var iChars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-";

   for (var i = 0; i < string.length; i++) {
      if (iChars.indexOf(string.charAt(i)) < 0)
         return false;
   }
   return true;
}

function isSafe(string) 
	{
	
   	if (string.length < 3) return false;

	if (!string) return false;
   	
	var iChars = "*|,\":<>[]{}`\';()&$#%";

   for (var i = 0; i < string.length; i++) {
      if (iChars.indexOf(string.charAt(i)) != -1)
         return false;
   }
   return true;
   }

		  
function isEmail(string)
{   
	var i = 1;
    var sLength = string.length;

    // look for @
    while ((i < sLength) && (string.charAt(i) != "@"))
    { i++
    }

    if ((i >= sLength) || (string.charAt(i) != "@")) return false;
    else i += 2;

    // look for .
    while ((i < sLength) && (string.charAt(i) != "."))
    { i++
    }

    // there must be at least one character after the .
    if ((i >= sLength - 1) || (string.charAt(i) != ".")) return false;
    else return true;
}