javascript数组取交集

和网友们讨论了数组取交集的方法，下面是两个实现

arr1=["1","5","6","7","8","9","10","11","12","13","17","93","7","74","12","76","19","21","33","12"],arr2=["1","2","3","4","17","12","61","12","75","13","17","23","8","97","64","24","93","43","75","13","88","25","21","26","7","5","9","33","28"],取交集<script>var arr1=["1","5","6","7","8","9","10","11","12","13","17","93","7","74","12","76","19","21","33","12"],arr2=["1","2","3","4","17","12","61","12","75","13","17","23","8","97","64","24","93","43","75","13","88","25","21","26","7","5","9","33","28"],hash={},intersect={},res=[];for(var i=0,l=arr1.length;i<l;i++)hash[arr1[i]]=true;for(var i=0,l=arr2.length;i<l;i++)hash[arr2[i]]&&(intersect[arr2[i]]=true);for(var k in intersect)res.push(k);alert(res);</script>

arr1=["1","5","6","7","8","9","10","11","12","13","17","93","7","74","12","76","19","21","33","12"],arr2=["1","2","3","4","17","12","61","12","75","13","17","23","8","97","64","24","93","43","75","13","88","25","21","26","7","5","9","33","28"],取交集<script>var arr1=["1","5","6","7","8","9","10","11","12","13","17","93","7","74","12","76","19","21","33","12"],arr2=["1","2","3","4","17","12","61","12","75","13","17","23","8","97","64","24","93","43","75","13","88","25","21","26","7","5","9","33","28"],intersect={},res=[];for (var i=arr1.length-1; i>=0; i--) {for ( var j=0; j<arr2.length; j++) {if (arr1[i]==arr2[j]) {intersect[arr1[i]]=true;}}}for(var k in intersect)res.push(k);alert(res);</script>