使用JavaScript实现隐藏/显示

function unhide(divID) {
    var unhidden = document.getElementsByClassName('unhidden');
    for (var k in unhidden) {
        unhidden[k].className='hidden';
    }

    var item = document.getElementById(divID);
    if (item) {
        item.className='unhidden';
    }
}
OlivierH：实现方法如下

function unhide(divID) {
    var divs = document.getElementsByTagName('div');
    foreach(var div in divs){
        div.className = 'hidden';
        if(div.id == divID)
            div.className = 'unhidden';
    } 
}
但需要注意 document.getElementsByTagName('div'); 它将返回你文档里的所有div，你可以选择给它封装起来。例如：
HTML

<div id="wrapper">
    <div id="text1" class="unhidden"> 
        This will show up when the Text 1 link is pressed.
    </div>
    <div id="text2" class="hidden"> 
        This will show up when the Text 2 link is pressed.
    </div>
    <div id="text3" class="hidden">
        This will show up when the Text 3 link is pressed.
    </div>
</div>
JS

var divs = document.getElementById('wrapper').getElementsByTagName('div');
Andrew：下面这中方法也适用，DEMO：http://jsfiddle.net/L79H7/1/点击预览

function unhide(divID) {

       var divIds = [ "text1", "text2", "text3" ];
       for ( var i = 0, len = divIds.length; i < len; i++) {
           var item = document.getElementById(divIds[i]);
           if (item) {

               item.className = divID == divIds[i] ? 'unhidden' : 'hidden';

           }
       }

   }
Dropout：其实你并不需要链接，只要能实现功能即可。
HTML

<p onclick="unhide('text1')">Text 1</p> 
<p onclick="unhide('text2')">Text 2</p>
<p onclick="unhide('text3')">Text 3</p>
<div id="text1" class="unhidden"> 
This will show up when the Text 1 link is pressed.
</div>
<div id="text2" class="hidden"> 
This will show up when the Text 2 link is pressed.
</div>
<div id="text3" class="hidden">
This will show up when the Text 3 link is pressed.
</div>
JS

function unhide(id){
    yourElement = document.getElementById(id);
    if(yourElement.className == "unhidden"){
        yourElement.className = "hidden";
        }else{
        yourElement.className = "unhidden";
    }        
}