var defaultEmptyOK = false;
var whitespace = " \t\n\r";

function errorMessage(element, message)
{
		alert(message);
		element.focus();
		return false;
}

// Check whether string s is empty.

function isEmpty(s)
{   return ((s == null) || (s.length == 0));
}

// Returns true if character c is a digit 
// (0 .. 9).

function isDigit (c)
{   return ((c >= "0") && (c <= "9"));
}

// Returns true if string s is empty or 
// whitespace characters only.

function isWhitespace (s)

{   var i;

    // Is s empty?
    if (isEmpty(s)) return true;

    // Search through string's characters one by one
    // until we find a non-whitespace character.
    // When we do, return false; if we don't, return true.

    for (i = 0; i < s.length; i++)
    {   
        // Check that current character isn't whitespace.
        var c = s.charAt(i);

        if (whitespace.indexOf(c) == -1) return false;
    }

    // All characters are whitespace.
    return true;
}


// isInteger (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if all characters in string s are numbers.
//
// Accepts non-signed integers only. Does not accept floating 
// point, exponential notation, etc.
//
// We don't use parseInt because that would accept a string
// with trailing non-numeric characters.
//
// By default, returns defaultEmptyOK if s is empty.
// There is an optional second argument called emptyOK.
// emptyOK is used to override for a single function call
//      the default behavior which is specified globally by
//      defaultEmptyOK.
// If emptyOK is false (or any value other than true), 
//      the function will return false if s is empty.
// If emptyOK is true, the function will return true if s is empty.
//
// EXAMPLE FUNCTION CALL:     RESULT:
// isInteger ("5")            true 
// isInteger ("")             defaultEmptyOK
// isInteger ("-5")           false
// isInteger ("", true)       true
// isInteger ("", false)      false
// isInteger ("5", false)     true

function isInteger (s)

{   var i;

    if (isEmpty(s)) 
       if (isInteger.arguments.length == 1) return defaultEmptyOK;
       else return (isInteger.arguments[1] == true);

    // Search through string's characters one by one
    // until we find a non-numeric character.
    // When we do, return false; if we don't, return true.

    for (i = 0; i < s.length; i++)
    {   
        // Check that current character is number.
        var c = s.charAt(i);

        if (!isDigit(c)) return false;
    }

    // All characters are numbers.
    return true;
}

function checkNumeric(field,limit,maxvalue)
{
		pattern = /^[0-9]*$/;
		if(pattern.test(field.value)==false)
		{
			return errorMessage(form.field, "Please enter a number in " + field.name);
			//alert("Not numeric in " + field.name);
			//field.value = 0;
			//return false;
		}
		
		if(field.length > limit)
		{
				return errorMessage(form.field, "Out of range in " + field.name);
				//alert("Out of range in " + field.name);
				//field.value = 0;
				//return false;
		}
			
		if(field.value > maxvalue)
		{
				return errorMessage(form.field, "Max value should be " + maxvalue);
		}
}


function safeEmail(field)
{
		pattern = /^[a-zA-Z_0-9.]*$/;
		
		if(field.value.length < 1){
			return errorMessage(form.field, "You must supply your preferred email");
		}
		
		
		if(pattern.test(field.value)==false)
		{
			return errorMessage(form.field, "Email not in correct format");
			//alert("Not numeric in " + field.name);
			//field.value = 0;
			//return false;
		}
}

// JavaScript Document

// isEmail (STRING s [, BOOLEAN emptyOK])
// 
// Email address must be of form a@b.c -- in other words:
// * there must be at least one character before the @
// * there must be at least one character before and after the .
// * the characters @ and . are both required
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.

function isEmail (s)
{   if (isEmpty(s)) 
       if (isEmail.arguments.length == 1) return defaultEmptyOK;
       else return (isEmail.arguments[1] == true);
   
    // is s whitespace?
    if (isWhitespace(s)) return false;
    
    // there must be >= 1 character before @, so we
    // start looking at character position 1 
    // (i.e. second character)
    var i = 1;
    var sLength = s.length;

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

    if ((i >= sLength) || (s.charAt(i) != "@"))
	{
		return false;
	}
	else
	{
		i += 2;
	}
    // look for .
    while ((i < sLength) && (s.charAt(i) != "."))
    { i++;
    }

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