'same as billing address' issue on checkout page

GREAT call. I was researching all the other topics on this, since author has not fixed it.

And this is the answer. I added JS to my wordpress system, to resolve this issue:

$(document).ready(function() {
   if (!jQuery('input[type=checkbox][name*="shippingSameBilling"]').prop('checked')) jQuery('input[type=checkbox][name*="shippingSameBilling"]').trigger('click');
});

I had not thought of that, until you que’d it. Thanks!!
So basically it forces it to be checked by default. I would rather force people to click a checkbox and retype values, than suffer this impassable error.

Here’s my complete fix for this issue.

<script type="text/javascript">

// include this function somewhere
function WPECOM_BUGFIX(options) {
	var target=jQuery('input[type=checkbox][name*="shippingSameBilling"]');
	if (target.length > 0) {

		if (options.force_shippingSameAsBilling) {
			if (!target.prop('checked')) target.trigger('click'); // have to trigger click, as the .prop() won't hide the inputs automatically.
		}

		if (options.force_valueMatch) {

			var form=$('form.wpsc_checkout_forms');
			form.on('submit',function(event) {
				if (options.force_valueMatch) {
					if (target.prop('checked')) {
						var billing_root=form.find('table input[data-wpsc-meta-key^="billing"]:not(.wpsc-meta-value):first').parents('table');
						var shipping_root=form.find('table input[data-wpsc-meta-key^="shipping"]:not(.wpsc-meta-value):first').parents('table');
						shipping_root.find('input[data-wpsc-meta-key*="i"]') // all of them have a letter i in their attribute(sh[i]pping, b[i]lling). This is simply to test for existence of the attribute, without having to run a jquery filter. Because none of these share a class or anything to identify them distinctly....
						.each(function() {
							var ident=$(this).data('wpscMetaKey').replace('shipping','');
							var assigned_el=billing_root.find('input[data-wpsc-meta-key*="'+ident+'"]'); // find the associated billing input.
							var assigned_value=assigned_el.val();
							$(this).val(assigned_value); // copy it's value over.
						});
					}
				}	

			});
		}
	}
}

</script>

and the execution on page load..

$(document).ready(function() {
	// call this on page load.
	// both options should be turned on, in order to fix the issue with AutoComplete filling entries without keystroke events, and to prevent php errors in WPEcom from failed submit forms.
	// this is due to incorrect validation when Shipping should be same as Billing. An ongoing issue for at least 8 months.
	WPECOM_BUGFIX({
		force_shippingSameAsBilling: true, // enable the checkbox by default, to support the following two methods. User will have to uncheck it to enter shipping info.
		force_valueMatch: true // force the values of shipping to match billing
	});
});

Am unsure why the php code hasn’t been updated for this. It shouldn’t be validating form fields whose values are empty due to a conditional checkbox.
So the above code simply copies the values over, onSubmit. Preventing user difficulty. They have simply to uncheck the box if they wish to input shipping information.