<div style="background: red; height: 40px; "></div>
  
 
 

  

   <div style="background: green; height: 70px;"></div>
  
 
 

  

   <div style="background: blue; height: 50px; "></div>
  
 
 

  

    
  
 
 

  

   <script>
  
 
 

  

   $.fn.equalizeHeights = function() {
  
 
 

  

    var maxHeight = this.map(function( i, e ) {
  
 
 

  

    return $( e ).height();
  
 
 

  

    }).get();
  
 
 

  

    return this.height( Math.max.apply( this, maxHeight ) );
  
 
 

  

   };
  
 
 

  

    
  
 
 

  

   $( "input" ).click(function() {
  
 
 

  

    $( "div" ).equalizeHeights();
  
 
 

  

   });
  
 
 

  

   </script>