<script type="text/javascript">
<!--
  var arr1=["1","2","3"],arr2;
  arr2=arr1.slice(0);
  arr1[0]=0; //改变arr1第一个元素
  alert("arr2[0]："+arr2[0]); //不影响arr2
  var arr3=["1","2","3"],arr4;
  arr4=arr3.concat();
  arr3[0]= 0; //改变arr3第一个元素
  alert("arr4[0]："+arr4[0]); //不影响arr4
</script>

<script type="text/javascript">
<!--
  var a1=[["1","2","3"],"2","3"],a2;
  a2=a1.slice(0);
  a1[0][0]=0; //改变a1第一个元素中的第一个元素
  alert(a2[0][0]); //影响到了a2
-->
</script>

<script type="text/javascript">
<!--
  function extend(destination,source)
  {
    for(var property in source)
    {destination[property]=source[property];}
  }
-->
</script>

<script type="text/javascript">
<!--
  function getType(o)
  {
    var _t;
    return ((_t = typeof(o)) == "object" "null" || Object.prototype.toString.call(o).slice(8,-1):_t).toLowerCase();
  }
  function extend(destination,source)
  {
    for(var p in source)
    {
      if(getType(source[p])=="array"||getType(source[p])=="object")
      {
        destination[p]=getType(source[p])=="array""ss",b:"dd",c:{d:"css",e:"cdd"}};
  var test1={};
  extend(test1,test);
  test1.c.d="change"; //改变test1的c属性对象的d属性
  alert(test.c.d); //不影响test
-->
</script>