function getForm()
{
      return document.form1;
}

function checkVld(){
            var f=getForm();
	banhang_category=f.banhang_category.value;
            banhang_name = f.banhang_name.value;
	banhang_address = f.banhang_address.value;	
	banhang_tel = f.banhang_tel.value;
            banhang_email = f.banhang_email.value;
			
	if (banhang_category=="0")
				{
					alert( " Xin quy khach vui long chon dich vu muon su dung !" );
					f.banhang_category.focus();
					return false;
				}
	if (banhang_name=="")
				{
					alert( " Xin quy khach vui long nhap ten cua minh !" );
					f.banhang_name.focus();
					return false;
				}
            if ( trim(banhang_name)=="")
				{
					alert( "Ten quy khach phai khac rong !" );
					f.banhang_name.focus();
					return false;
				}
	if (banhang_address=="")
				{
					alert( " Xin quy khach vui long nhap dia chi cua minh !" );
					f.banhang_address.focus();
					return false;
				}
            if ( trim(banhang_address)=="")
				{
					alert( "Dia chi cua quy khach phai khac rong !" );
					f.banhang_address.focus();
					return false;
				}
	if (banhang_tel=="")
				{
					alert( " Xin quy khach vui long nhap so dien thoai de chung toi lien he !" );
					f.banhang_tel.focus();
					return false;
				}
            if ( trim(banhang_tel)=="")
				{
					alert( "éo dien thoai cua quy khach phai khac rong !" );
					f.banhang_tel.focus();
					return false;
				}
			
	if (banhang_email=="")
				{
					alert( "Xin quy khach vui long nhap dia chi Email cua minh!" );
					f.banhang_email.focus();
					return false;
				}

	if ( trim(banhang_email)=="")
				{
					alert( "Dia chi cua quy khach phai khac rong !" );
					f.banhang_email.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;
}