join in array

JavaScript
var a = ['Wind', 'Water', 'Fire'];
a.join();      // 'Wind,Water,Fire'
a.join(', ');  // 'Wind, Water, Fire'
a.join(' + '); // 'Wind + Water + Fire'
a.join('');    // 'WindWaterFire'<html>
  <select multiple class="select-colors">
    <option>blue</option>
    <option>green</option>
  </select>
</html>  

<script>
  var myColorSelect = $(".select-colors").val().join();
  
 console.log(myColorSelect);
</script>
Source