how to add special characters in string in js code example

Example 1: javascript html special characters

return mystring.replace(/&/g, "&amp;").replace(/>/g, "&gt;").replace(/</g, "&lt;").replace(/"/g, "&quot;");

Example 2: javascript have special characters

var format = /[ `!@#$%^&*()_+\-=\[\]{};':"\\|,.<>\/?~]/;
//            ^                                       ^   
document.write(format.test("My@string-with(some%text)") + "<br/>");
document.write(format.test("My string with spaces") + "<br/>");
document.write(format.test("MyStringContainingNoSpecialChars"));