JavaScript

var ServiceUrl = function() {
  var src = document.currentScript.src;
  var idx = src.indexOf("/scripts");
  if (idx > 0) 
    src = src.substring(0, idx);
  else
    src = "";
  return src;
}();

if (!getServiceUrl) {
  function getServiceUrl() {
    return ServiceUrl;
  }
}

//------------------------
//use for asyn or sync load javascript file on demand.
if (typeof (include) == "undefined") {
  function include(url, type, cb, asIs) {
    asIs = asIs || false;
    cb = cb || null;
    if (!url) {
      console.log("No file specified to be loaded.");
      return;
    }
    if (!asIs)
      url = getServiceUrl() + url;

    var alreadyLoaded = false;
    // Adding the script tag to the head as suggested before
    if (type.indexOf("javascript") > 0) {
      var sc = document.scripts;
      var scExists = false;
      for (var i = 0, len = sc.length; i < len; i++) {
        //<script src="url"></script>
        var src = /src="(.*?)"/.exec(sc[i].outerHTML);
        if (src && src.length > 0) {
          if (src[1] == url) {
            scExists = true;
            break;
          }
        }
      }
      if (!scExists) {
        var el = document.createElement('script');
        el.type = type;
        el.src = url;
      }
      else
        alreadyLoaded = true;
    }
    else {
      var ss = document.styleSheets;
      var cssExists = false;
      for (var i = 0, max = ss.length; i < max; i++) {
        if (ss[i].href == url) {
          cssExists = true;
          break;
        }
      }

      if (!cssExists) {
        var el = document.createElement("link");
        el.href = url;
        el.type = type;
        el.rel = "stylesheet";
      }
      else
        alreadyLoaded = true;
    }

    if (el) {
      // Then bind the event to the callback function.
      // There are several events for cross browser compatibility.
      if (typeof (cb) == "function") {
        el.onload = cb;
      }

      // Fire the loading
      var head = document.getElementsByTagName('head')[0];
      head.appendChild(el);
    }

    if (alreadyLoaded) {
      if (typeof (cb) == "function") {
        cb();
      }
    }
  }
};

var url_to_open = BaseUrl + "?_encryptedMessage=" + yourEncryptedMessage;
window.open(url_to_open);

1. On click of your button, call a javascript function.
2. Get the gridview row data in Javascript variable (probably from dom attribute).
3. Put the data in Webform2 url query string.
4. In your webform2, read the data from query string.

.load() | jQuery API Documentation[^]

Load data from the server and place the returned HTML into the matched element.

JavaScript

$("#result").load("ajax/test.html");

{
"name" : ["Steve", "Jeremy"],
 "Age": [76,43]
}