3 Solutions for Supporting Internet Explorer (edit)
Support IE11
https://davidwalsh.name/supporting-internet-explorer
https://dzone.com/articles/debug-javascript-in-internet-explorer-11-in-7-easy
https://html5test.com/compare/browser/ie-11.html
ES6
https://ariya.io/2013/02/es6-and-object-literal-property-value-shorthand
HTML URL Encode
https://www.the-art-of-web.com/javascript/escape/
http://www.satyakomatineni.com/akc/display?url=DisplayNoteIMPURL&reportId=1721&ownerUserId=satya
https://www.w3schools.com/tags/ref_urlencode.asp
Code in View Razor (MVC5)
$('#Password').val('123456a@@');
$('#Password').val('123456a' + decodeURIComponent('%40'));