如何隱藏臨時列表項和重新出現切換按鈕

如何隱藏臨時列表項和重新出現切換按鈕後？當有隱藏物品時，可以通過它的ID找到它？如何隱藏臨時列表項和重新出現切換按鈕

function action(x) { 
    var parag = document.getElementById("li" + x); 
    if(parag.style.visibility = "hidden"){ 
     parag.style.visibility = "visible"; 
    }else{ 
     parag.style.visibility = "hidden"; 
    } 
}

要麼使用下面的不工作？

<head> 

<script type="text/javascript"> 

function action(x){ 
var parag=document.getElementById("li"+x); 
    if(parag.style.display=="none"){ 
     parag.style.display="block"; 
    }else{ 
     parag.style.display="none"; 
    } 
} 

</script> 
</head> 
<body> 

<ul> 
    <li id="li1">Item1</li> 
    <li id="li2">Item2</li> 
    <li id="li3">Item3</li> 
</ul> 
<form name="myform"><input type="button" onclick="alert(document.myform.select.value);action(document.myform.select.value)" value="show/hide"/><label> 
    <select name="select" id="select"> 
    <option value="1">1</option> 
    <option value="2">2</option> 
    <option value="3">3</option> 
    </select> 
</label></form> 
</body> 
</html>

來源

2012-06-14 Poliscarhire Cyprus