JavaScript的swichcase方法

function changeBody(index){  switch(index){  case 1:{  document.getElementById('bull').style.display = "";  document.getElementById('cont').style.display = "none";  document.getElementById('gridPager').style.display = "none";document.getElementById('dis').style.display = "none";break;      }  case 2:{  document.getElementById('bull').style.display = "none";  document.getElementById('cont').style.display = "";  document.getElementById('gridPager').style.display = "";document.getElementById('dis').style.display = "";break;      }  case 3:{  document.getElementById('bull').style.display = "none";  document.getElementById('cont').style.display = "";  document.getElementById('gridPager').style.display = "";document.getElementById('dis').style.display = "";break;      }    }}