如何使用JQuery定位变量的子对象

var post_ad = $(\'.duplicate_name\'); 
var post_ad_cloned = post_ad.clone().removeClass(\'duplicate_name\').appendTo(\'#sss\').show();
$(\"post_ad_cloned input\").css(\'color\', \'red\'); 

var post_ad = $(\'.duplicate_name\'); 
var post_ad_cloned = post_ad.clone().removeClass(\'duplicate_name\').appendTo(\'#sss\').show();
$(\"input\", post_ad_cloned).css(\'color\', \'red\'); 

var post_ad = $(\'.duplicate_name\'); 
var post_ad_cloned = post_ad.clone()
  .removeClass(\'duplicate_name\')
  .appendTo(\'#sss\')
  .show()
  .children(\'input\')
    .css(\'color\', \'red\');