function getForm()
{
      return document.form1;
}

function checkVld(){
            var f=getForm();
            feedback_name = f.feedback_name.value;
            feedback_tel = f.feedback_tel.value;
            feedback_email = f.feedback_email.value;
            feedback_Content = f.feedback_Content.value;
			
			if (feedback_name=="")
				{
					alert( " Xin quy khach vui long nhap ten cua minh!" );
					f.feedback_name.focus();
					return false;
				}
            if ( trim(feedback_name)=="")
				{
					alert( "Ten cua quy khach chua duoc khai bao!" );
					f.feedback_name.focus();
					return false;
				}
	if ( trim(feedback_tel)=="")
				{
					alert( "Xin quy khach vui long cho biet so dien thoai lien he!" );
					f.feedback_tel.focus();
					return false;
				}			
	if (feedback_email=="")
				{
					alert( " Xin quy khach vui long cho biet dia chi E-mail!" );
					f.feedback_email.focus();
					return false;
				}

	if ( trim(feedback_email)=="")
				{
					alert( "Quy khach chua khai bao dia chi E-mail!" );
					f.feedback_email.focus();
					return false;
				}		
	if (feedback_Content=="")
				{
					alert( "Xin quy khach vui long cho biet noi dung lien he!" );
					f.feedback_name.focus();
					return false;
				}
	
	return true;
}

function trim(s){
            var output='';

            i=0;
            while (s.charAt(i)==' ') { i++;}

            j=s.length-1;
            while (s.charAt(j)==' ') { j--; }

            for (k=i; k<=j; k++){

                    if ((s.charAt(k)==' ')&& (s.charAt(k+1)==' ')){

                    }else{
                            output = output + s.charAt(k);
                    }
            }
            return output;
}