JSFiddle - React, Tailwind, and code Playground

HTML

<div id="AssignCall" title="Assign Call" style="display:none;">
    <form id="AssignCallForm" method="post" action="ViewCalls.aspx"> <span id="ctl00_MainContent_AssignTo">Assign to:</span>

        <select name="ctl00$MainContent$AssignToDropDown" id="ctl00_MainContent_AssignToDropDown">
            <option value="Please Select">Please Select</option>
            <option value="test1">Test1</option>
        </select>
        <input type="hidden" name="ctl00$MainContent$Action" id="ctl00_MainContent_Action" value="AssignCall" />        
        <input type="submit" id="button" onclick="alert('clicked')" style="display:none;" />
    </form>
</div>

JavaScript

$(function () {
    $('#AssignCall').dialog({
        autoOpen: true,
        show: "fade",
        hide: "fade",
        modal: true,
        buttons: {
            "Ok": function () {
                $("#button").click();
                //$(this).dialog("close");
            },
                "Cancel": function () {
                $(this).dialog("close");
            }
        }
    });

});