function checkQuantity()
   {
     var q1, q2, q3;
     if($('ddlAmount1'))
       q1 = $('ddlAmount1').options[$('ddlAmount1').selectedIndex].value;
     else
       q1 = '-';

     if($('ddlAmount2'))
       q2 = $('ddlAmount2').options[$('ddlAmount2').selectedIndex].value;
     else
       q2 = '-';

     if($('ddlAmount3'))
       q3 = $('ddlAmount3').options[$('ddlAmount3').selectedIndex].value;
     else
       q3 = '-';

     var img = $('imgBtnPost');
     if(q1+q2+q3=='---')
     {
       img.src = img_dis_src;
       img.style.cursor = "default";
       img.disabled = true;
     }else{
       img.src = img_en_src;
       img.style.cursor = "pointer";
       img.disabled = false;
     }
   }