CodePen

HTML

            
              <div>
	<div class="box" id="first"></div>
	<div class="box" id="second"></div>
	<div class="box" id="third"></div>
</div>
            
          
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CSS

            
              div { width: 80%; height: 250px; background: #BADA55; margin: 0 auto; }

.box{ width: 355px; height: 100%; float: left; }

#first { background:#939; }

#second { background:#FF5; }

#third { background:#399; }
            
          
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JS

            
              
            
          
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