how to get jquery first class http://jsbin.com/aLERidIF/1/edit

firstClassName.js

$(function(){
  var first  = $('div').attr('class').replace(/^(\S*).*/, '$1');
  var second = $('div').attr('class').split(' ')[0];
  var third  = $('div').attr('class').split(' ').shift();
  var ArrayData = $.map($('div').attr('class').split(' '), function(value){
    return value;
  });
  var thirdFirst  = $('div').attr('class').split(' ').pop();

  
  console.log('first  :', first);  // 처음
  console.log('second :', second); // 처음
  console.log('third  :', third);  // 처음
  console.log('ArrayData first :', ArrayData[0]); //처음
  console.log('ArrayData last  :', ArrayData[ArrayData.length - 1]); // 마지막
  console.log('thirdFirst      :', thirdFirst); // 마지막
});