How to check for minimum quantity and show an alert without sending the form if quantity is less than X

l.settings:product:minimum_quantity is set by module or other page coding.

Most miva merchant quantity boxes are forms named "add".

If your quantity box form is named something else change the js below where it says name="add" to whatever the name of your form is. If there is no name, then
you can put one in like the simplified example form below.

<form method="post" action="&mvte:urls:BASK:secure;" name="add" onsubmit="return checkMinimum()">
	Quantity: <input type="number" name="Quantity">
	<button  type="submit" class="button">Add to Cart</button>
  </form>

<script>
function checkMinimum() {
	var total  = document.forms["add"]["Quantity"].value;
	if (total < &mvt:product:minimum_quantity;) {
		  alert('Minimum quantity is &mvt:product:forcemultiples:prefillquantity;. Your current quantity is ' + total + '.');
		return false;
	}
};
</script>