function IsNumeric(strString)
{
   var strValidChars = "0123456789-() ";
   var strChar;
   var blnResult = true;
   if (strString.length == 0) return false;

   for (i = 0; i < strString.length && blnResult == true; i++)
      {
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1)
         	{
        	 blnResult = false;
         	}
      }
   return blnResult;
}

function validateContact(thisform)
{ 
 
	with (thisform)
	{
		$('#submit_btn1').hide();$('#wait_btn1').show();
			//if (name.value==name.defaultValue) 
		if (emptyvalidation(name,"Woops! You forgot to fill your Name")==false) 
			{ 
			name.focus();
			$('#submit_btn1').show();$('#wait_btn1').hide();
			return false;
			}
		if (emptyvalidation(city,"Woops! You forgot to fill your City")==false) 
			{
				city.focus();
				$('#submit_btn1').show();$('#wait_btn1').hide();
				return false;
			}
			if (emptyvalidation(phone,"Woops! You forgot to fill your Phone Number")==false) 
			{
				phone.focus();
				$('#submit_btn1').show();$('#wait_btn1').hide();
				return false;
			}
			
		if (emptyvalidation(email,"Woops! You forgot to fill your Email Address")==false) 
			{
			email.focus();
			$('#submit_btn1').show();$('#wait_btn1').hide();
			return false;
			}
			if(emailvalidation(email)==false)
			{
				alert("Woops! You have entered an invalid Email Address");
				email.select();
				email.focus();
				$('#submit_btn1').show();$('#wait_btn1').hide();
				return false;
			}
			
			
			
			if (emptyvalidation(comments,"Woops! You forgot to fill your Comments")==false)
			{
				comments.focus();
				$('#submit_btn1').show();$('#wait_btn1').hide();
				return false;
			}
			if(userdigit1.value=="Enter Verification Code")userdigit1.value="";
			if (emptyvalidation(userdigit1,"Woops! You forgot to fill  Verification Code")==false) 
			{
				userdigit1.select();
				userdigit1.focus();
				$('#submit_btn1').show();$('#wait_btn1').hide();
				return false;
			}
		 runAjax1('check_captcha1','process_mail_contact.php',document.contact_form1.userdigit1.value);
	 return false;
 }
 return true;
}
function captcha_refresh1()
{
document.getElementById("button_div1").src='button-contact.php?'+Math.random();
return false;
}
<!--Ajax for checking the captcha code ends here -->
var xmlHttp
function runAjax1(field,argurl,argVal)
{
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
{
alert ("Browser does not support HTTP Request")
return
} 
var url=argurl
url=url+"?userdigit="+argVal
url=url+"&sid="+Math.random()
if(field=='check_captcha1')
xmlHttp.onreadystatechange=check_captcha1;
xmlHttp.open("POST",url,true)
xmlHttp.send(null)
}
function check_captcha1() 
{ 
	if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
	{ 
			
			if(xmlHttp.responseText=="yes")
			{
			$('#submit_btn1').hide();$('#wait_btn1').show();
			 	document.contact_form1.submit();
			}
			else
			{
				captcha_refresh1();
				alert("Verification Code Mismatch");
				document.contact_form1.userdigit1.focus();
				document.contact_form1.userdigit1.select();
				$('#submit_btn1').show();$('#wait_btn1').hide();
				return false;
			}
			
	} 
} 
function GetXmlHttpObject()
{ 
	var objXMLHttp=null
if (window.XMLHttpRequest)
{
	objXMLHttp=new XMLHttpRequest()
}
else if (window.ActiveXObject)
{
	objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP")
}
	return objXMLHttp
}