How to display popup in center of the screen in mvc using jquery

<section class="msg-pop" id="ApplyMBox">
    <span class="msg-pop-head"><span class="msg-headtext"><h3 id="ApplyHead"></h3></span></span>
    <section class="share-pop-inr">
        <span class="clr"><label id="ApplyMsg"></label></span>
        <section class="ok-button">
            <input type="button" value="OK" class="butn-style-01 shr-btn-02" name="" id="Updatepopbtn">

            <span class="clr"></span>
        </section>
        <!-- stop: share privacy settings -->
        <span class="clr"></span>
    </section>
    <span class="clr"></span>
</section>

function ApplyComplete() {
        if ($("#ApplyTarget").contents().find("#ApplyStatus").length > 0) {
            var res = $("#ApplyTarget").contents().find("#ApplyStatus").html();
            $("#ApplyHead").html("Message");
            $("#ApplyMsg").html(res);
            $("#ApplyMBox").show();
            $("#ApplyMBox").center();
            $("#ApplyBG").show();
        }
    }


 jQuery.fn.center = function () {
        this.css("position", "absolute");
        this.css("top", Math.max(0, (($(window).height() - $("#ApplyMBox").outerHeight()) / 2) +                                    $(window).scrollTop()) + "px");
        this.css("left", Math.max(0, (($(window).width() - $("#ApplyMBox").outerWidth()) / 2) +
                                                    $(window).scrollLeft()) + "px");

        return this;
    }