Making checkout fields required

Sometimes as part of the checkout you need to ensure that customers are providing their phone number or company names. To do that, simply paste the following relevant script right before the closing </head> tag of your checkout template.

<script type="text/javascript" charset="utf-8">
  jQuery(document).ready(function(){
    jQuery("#customer_phone").addClass("fc_required");
    jQuery("li.fc_customer_phone label.fc_pre").append("<span class=\"fc_ast\">*<\/span>");
    jQuery("#customer_phone").blur(function() {
    if (this.value == "") {
      FC.checkout.updateErrorDisplay(this.name,true);
    } else {
      FC.checkout.updateErrorDisplay(this.name,false);
    }
   });
});
</script>

<script type="text/javascript" charset="utf-8">
jQuery(document).ready(function(){
  jQuery("li.fc_customer_company").children("label.fc_pre").html("Company<span class=\"fc_ast\">*</span>");
  jQuery("#customer_company").addClass("fc_required");
  jQuery("#customer_company").blur(function() {
    if (this.value == "") {
      FC.checkout.updateErrorDisplay(this.name,true);
    } else {
      FC.checkout.updateErrorDisplay(this.name,false);
    }
  });
});
</script>

http://forum.foxycart.com/comments.php?DiscussionID=5077&page=1#Item_3 http://forum.foxycart.com/comments.php?DiscussionID=200&page=1#Item_14