CodePen

HTML

            
              <select class='selectList' multiple="multiple">
  <option value="value1">value1</option>
  <option value="value2">value2</option>
  <option value="value3">value3 has a really long display string</option>
  <option value="value4">value4</option>
  <option value="value5">value5</option>
  <option value="value6">value6</option>
  <option value="value7">value7</option>
  <option value="value8">value8</option>
</select>
            
          
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CSS

            
              .selectList{
  margin: 20px;
  width: 200px;
  height: 150px;
  overflow-x: scroll;  
}
            
          
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JS

            
              
            
          
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