jsは2つの配列の同じ要素をフィルタします

  
  



  var arry1 = ['a','b','c','d'];

  var arry2 = ['x','b','c','y'];

  var arry3 = new Array();

  var j = 0;

  for(var i=0;i<arry1.length;i++){

    for(var k=0;k<arry2.length;k++){

      if(arry1[i]==arry2[k]){

        arry3[j]=arry1[i];

        ++j;



      }

    }

  }

  //array3      ['b','c']

  console.log(arry3);