You can target an element that has no child elements by using the :empty pseudo-class. With browser support down to IE9, it's solid, easy way to select empty elements without any additional markup.

Be aware that whitespace is considered a "child", so :empty will not work if the element has no children, but has space between the opening and closing tags.

 

  
       
       
     
    
      
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.Alert:not(:empty) {
     border: 3px solid darkgreen;  margin: 1em;  padding: 1em;  background-color: seagreen;  color: white;  border-radius: 4px;}.Alert:empty{
     display:none;}