01.<script>
02.function chkform(){
03.if(window.document.myform.Post_company.value==""){
04.alert("ใส่ค่าที่ต้องการ");
05.}
06.}
07.</script>
08.<form id="myform" name="myform" action="j_Insert.php" method="post" Onsubmit="chkform()">
09.<input type='radio' name='Post_company' id='Post_company'>
10.<input type="Submit" name="submit" value="ตกลง">
11.</form>
