Store data-value from select option with js

HTML

<select name="mySelect" class="myselectClass" id="mySelect">
    <option value="myval0">test 0</option>
    <option value="myval1">test 1</option>
    <option value="myval2">test 2</option>
</select>
<br>
<input type="submit" id="mysave" value="Save" />

JavaScript

$(function(){
    $("#mysave").on('click', function(){
        var i = $("#mySelect").prop("selectedIndex");
        var t = $("#mySelect option:selected").text() == test0;
        alert("Index: " + i + " is " + t);
    });
});