How do I compare two variables containing strings in JavaScript?
=== is not necessary. You know both values are strings so you dont need to compare types.
function do_check()
{
var str1 = $("#textbox1").val();
var str2 = $("#textbox2").val();
if (str1 == str2)
{
$(":text").removeClass("incorrect");
alert("equal");
}
else
{
$(":text").addClass("incorrect");
alert("not equal");
}
}.incorrect
{
background: #ff8888;
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input id="textbox1" type="text">
<input id="textbox2" type="text">
<button onclick="do_check()">check</button>instead of using the == sign, more safer use the === sign when compare, the code that you post is work well