// JavaScript Document

function checkEmail(email)
{	
   var at1      =  email.indexOf("@");
   var at2      =  email.lastIndexOf("@");
   var dot     =  email.lastIndexOf(".");
   var space   =  email.indexOf(" ");
   var errormsg="";
   if((at1!=-1)&&
      (at1!=0)&&
      (at2==at1)&&
      (dot!=-1)&&
      (dot>at1+1)&&
      (dot<email.length-1)&&
      (space==-1))
   {
      return true;
   }
   else
   {
      errormsg=errormsg+"- Email chua nhap hoac sai dinh dang.\n";
	  alert(errormsg);	
	  document.formcontact.txtemail.value="";
      return false;
   }
}

function setStyle(field)
{
	if(field.value!="")
		{
			field.style.background="white";
			field.style.color="black";			
			}		
	//else
		//{
		//	checkForm(field,"Xin vui long nhap du lieu cho textbox nay");
		//	}
	}
	
function checkForm(colorBack,colorText)
{
	if(document.formcontact.txthoTen.value=='')
		{
			alert("Please fill your information into textbox!");
			document.formcontact.txthoTen.focus();
			document.formcontact.txthoTen.style.background=colorBack;
			document.formcontact.txthoTen.style.color=colorText;
			}
	else if(document.formcontact.txtdienThoai.value=='')
		{
			alert("Please fill your phone number into textbox!");
			document.formcontact.txtdienThoai.focus();
			document.formcontact.txtdienThoai.style.background=colorBack;
			document.formcontact.txtdienThoai.style.color=colorText;			
			return false;
		}	
	else if(document.formcontact.txtdiaChi.value=='')
		{
			alert("Please fill your address into textbox!");
			document.formcontact.txtdiaChi.focus();
			document.formcontact.txtdiaChi.style.background=colorBack;
			document.formcontact.txtdiaChi.style.color=colorText;			
			return false;
		}		
	else if(document.formcontact.txtemail.value=='')
		{
			alert("Please fill your email into textbox!");
			document.formcontact.txtemail.focus();
			document.formcontact.txtemail.style.background=colorBack;
			document.formcontact.txtemail.style.color=colorText;
			return false;
		}	
	/*else if
		{
			if(checkEmail(document.formcontact.txtemail.value) ==false )
				{
						alert("Dia chi email khong hop le!");
						document.formcontact.txtemail.value="";
						document.formcontact.txtemail.focus();
					}
			}	*/
	else if(document.formcontact.txtnoiDung.value=='')
		{
			alert("Please fill content into textbox!");
			document.formcontact.txtnoiDung.focus();
			document.formcontact.txtnoiDung.style.background=colorBack;
			document.formcontact.txtnoiDung.style.color=colorText;			
			return false;
		}		
	else
		{
			document.formcontact.submit();
			}
	}