How to place this correct with position css?

Question

I have a < div > with weight:100% and a button should be placed on the right. But my code doesn't work. May anyone help me to find out why?

<div style="width:100%">
   <span>some text</span>
   <input style="position:relative; right:0px;" type="button"/>
</div>

Answer 1

Div must me relative and button absolute.

 <div style="width:100%; position: relative;">
    <span>some text</span>
    <input style="position:absolute; right: 0px;" type="button"/>
 </div>