I'm using JQM datebox as following now:
<input name="startTime" id="startTime" type="text" data-role="datebox" data-options={"mode": "datebox"}>
But the datebox doesn't pop up at the center of window.
How can I to do it?
You can force the Position of the PopUp: http://dev.jtsage.com/jQM-DateBox/api/popupPosition/
Example 1 (http://jsfiddle.net/Twisty/6swq0t0k/1/):
<input name="startTime" id="startTime" type="text" data-role="datebox" data-options='{ "mode": "datebox", "popupPosition": "window"}' />
Example 2:
<input name="startTime" id="startTime" type="text" />
<script>
$("#startTime").datebox({
mode: "datebox",
popupPosition: "window"
});
</script>
This will force it to center in browser window. You can also center over another element by it's ID if you want.