The follwing ajax script isn't sending data to php, the page just reloads & form input values are passed onto the url.
Script
<script>
$("#addProducts").submit(function(event) {
var str = $("addProducts").serialize();
event.preventDefault();
$.ajax({
type: "POST",
url: "subAddProduct.php",
data:str
})
});
</script>
HTML Form
<form enctype="multipart/form-data" id="addProducts">
...
</form>