function validate_form() {
  var currentForm = document.contactus;
  if (currentForm.yourname.value == "")
  {	
    alert("Please enter your full name");
  	currentForm.yourname.focus();
  	return false;
  }
  if (!validName(currentForm.yourname.value)) {
     alert("You've enter an invalid name");
     currentForm.yourname.focus();
     return false;
  } 
  if (currentForm.contact_no.value == "")
  {	
    alert("Please enter your Contact number");
  	currentForm.contact_no.focus();
  	return false;
  }
    if(!validPhone(currentForm.contact_no)) { return false; }

  if (currentForm.emailaddress.value == "")
  {	
    alert("Please enter your email address");
  	currentForm.emailaddress.focus();
  	return false;
  }
    if (!validEmail(currentForm.emailaddress)) {
     alert("You've enter an invalid email address");
     currentForm.emailaddress.focus();
     return false;
  } 

  if (currentForm.message.value == "")
  {	
	alert("Please enter your message");
  	currentForm.message.focus();
  	return false;
  }    
}



function validEmail(email) {
	if (email.value.length > 0) {
		var filter = /^[a-zA-Z0-9]([a-zA-Z0-9_\.\-\+])*\@([a-zA-Z0-9]([a-zA-Z0-9\-])*\.)+([a-zA-Z0-9])+$/;
		var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/ ;

		if (!filter.test(email.value)) {			
		        return false;
		}
		else if (email.value.match(illegalChars)) {
				return false;
		} 

	}
	return true;
}

function validName(alphane)
{
	var numaric = alphane;
	for(var j=0; j<numaric.length; j++)
		{
		  var alphaa = numaric.charAt(j);
		  var hh = alphaa.charCodeAt(0);
		  if( (hh > 31 && hh<33)  || (hh > 64 && hh<91) || (hh > 96 && hh<123))
		  {
		  }
			else	{
				return false;
			}
		}
 return true;
}

function validPhone(fld) {
    var error = "";
    var stripped = fld.value.replace(/[\(\)\.\-\ ]/g, '');    

    if (isNaN(parseInt(stripped))) {
        alert("Please enter a valid phone number.");
		fld.focus(); 
	    return false;
    } else if (!(stripped.length >= 8)) {
        alert("Please enter a valid phone number.");
		fld.focus(); 
	    return false;
    }
	else { return true; }
}