how to escape string in javascript code example

Example 1: javascript escape html

function escapeHtml(str) {
    return str.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/"/g, "&quot;").replace(/'/g, "&#039;");
}

Example 2: javascript escape single quote

document.getElementById("something").innerHTML = "<img src='something' onmouseover='change(\"ex1\")' />";

Example 3: javascript escape single quote

var string = 'this isn\'t a double quoted string';
var string = "this isn\"t a single quoted string";
//           ^         ^ same types, hence we need to escape it with a backslash