Get all child’s width jquery

<ul>
  <li>AAA</li>
  <li>AAA</li>
  <li>AAA</li>
  <li>AAA</li>
</ul>

var ul_width = 0;
jQuery( 'ul li' ).each(function(index, element) {  
  ul_width += jQuery( this ).innerWidth;   
});
jQuery( 'ul' ).each(function(index, element) {  
  jQuery( this ).width(ul_width);   
});