How can I remove underline of link using CSS and JQuery?

There are four links with <a> label in my webpage, I hope to redirect to new webpage and remove the underline of the link when I click a link.

The Code A can redirect new webpage when I click a link, but the underline of the link can’t be removed.

The Code B can remove the underline of the link when I click a link, but webpage can’t be redirected, how to fix it?

Code A

       $(function () {
            $(".mainMenu").click(function () {
                $(".mainMenu").removeClass("mainMenuSelected").addClass("mainMenu");        
                $(this).addClass("mainMenuSelected");
            });
        });



   <a id="id_home"  href="/Default.aspx"  class="mainMenu" >Home</a>
    <a id="id_demo"  href="/Demo.aspx"  class="mainMenu">Demo</a>
    <a id="id_help"  href="/Help.aspx"  class="mainMenu">Help</a>
    <a id="id_about" href="/About.aspx"  class="mainMenu">About</a>

.mainMenu {
    font-size: 20px;
    margin-right: 25px;    
}


.mainMenuSelected {
    text-decoration: none;
    color: Blue;
}

Code B

       $(function () {
            $(".mainMenu").click(function () {
                $(".mainMenu").removeClass("mainMenuSelected").addClass("mainMenu");        
                $(this).removeAttr("href").addClass("mainMenuSelected");
            });
        });

...//The same

Added Content:

The following Code C is my answer, it works well.

Code C

$(function () {
            var filename = window.location.pathname.split('/').pop();

            switch (filename.toUpperCase()) {
                case "Default.aspx".toUpperCase():
                    setMainMenuSelected("#id_home");
                    break;

                case "":
                    setMainMenuSelected("#id_home");
                    break;

                case "Demo.aspx".toUpperCase():
                    setMainMenuSelected("#id_demo");
                    break;

                case "Help.aspx".toUpperCase():
                    setMainMenuSelected("#id_help");
                    break;

                case "About.aspx".toUpperCase():
                    setMainMenuSelected("#id_about");
                    break;

            }

        });

        function setMainMenuSelected(id) {
            $(id).removeAttr("href").addClass("mainMenuSelected");
        }