JS做的全选和取消全选

-----------------------------html-----------------------------------------

<input type="checkbox" name="test"/>1<input type="checkbox" name="test"/>2<input type="checkbox" name="test" />3<input type="checkbox" name="test" />4<input type="checkbox" name="test" />5<input type="checkbox" id="chooseall" onclick="selectAll()"/>全选

-------------------------js-----------------------------------

var chooseall=document.getElementById("chooseall"),   mytest=document.getElementsByName("test"),   leng=mytest.length;function selectAll(){   if(chooseall.checked==true){      for(i=0;i<leng;i++){         mytest[i].checked=true;      }   }else{      for(i=0;i<leng;i++){         mytest[i].checked=false;      }   }}