Issue with jQuery and Gravity form

Having a little trouble with some jQuery & Gravity Forms.

I added some Jquery to it to add a plus and minus button to increase and decrease the value in a number field but when I submit the form it just resets the form and the problem seems to lie within that script for the number functionality.

jQuery(document).ready(function($){
$(".ginput_container_number").append('<div class="inc button">+</div><div class="dec button">-</div>');
$(".button").on("click",function(){
var $button=$(this);
var oldValue=$button.parent().find("input").val();
if($button.text()=="+"){
var newVal=parseFloat(oldValue)+1;

} else {
if(oldValue>0){
var newVal=parseFloat(oldValue)-1;
} else {
newVal=0;
}
}
$button.parent().find("input").val(newVal);
});
});

You can find the form here:

https://john++++++++hl.com/track/

and the script is at http://na++++++idel.com/john++++++++hl.com/wp-content/themes/sc-platform/js/custom.js