For trial sales page. Will inject + lock down any form field that is sent in through the URL (by the input ID)

custom_infusionsoft_snippet.html

<script>
    function getParameterByName(name, url) {
        if (!url) url = window.location.href;
        name = name.replace(/[\[\]]/g, "\\$&");
        var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
            results = regex.exec(url);
        if (!results) return null;
        if (!results[2]) return '';
        return decodeURIComponent(results[2].replace(/\+/g, " "));
    };
    function createCookie(name, value, days) {
          var expires;
          if (days) {
              var date = new Date();
              date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
              expires = "; expires=" + date.toGMTString();
          }else{
              expires = "";
          };
          document.cookie = encodeURIComponent(name) + "=" + encodeURIComponent(value) + expires + "; path=/";
    };
    
    jQuery(document).ready(function () {
      document.querySelectorAll('input').forEach(function(input){
       if(input.id && getParameterByName(input.id)){
        jQuery('#'+input.id).val(getParameterByName(input.id));
        jQuery('#'+input.id).prop('disabled', true);
       };
      });
      
      
      //if affiliate in url, set to cookies
      var affiliate = getParameterByName('affiliate');
      if(affiliate){
      	createCookie('affiliate', affiliate, 30);
      };
  });
</script>