// JavaScript Document
function $(obj){ 
    return document.getElementById(obj); 
} 
window.onload = function(){ 
    var table = document.getElementById("myTable"); 
    //如果在表格区域内产生单击 
    table.onclick = function(e){ 
        var e = window.event||e,target = e.srcElement||e.target; 
         
        //得到tr 
        while(target.tagName.toLowerCase() != "tr"){ 
            target = target.parentNode; 
        } 
         
        var i = target.rowIndex; 
        //单击单行的Tr的话就是控制tr + 1的隐藏和显示 
          
        if(i%2 == 0){ 
                        var nrs = table.rows[i + 1].parentNode.style; 
            nrs.display = nrs.display == "none"?"":"none"; 
        } 
    } 
}