Prototype 似乎已经过气了，但用的人还是挺多，这段代码是用来实现即时文本编辑(Edit In Place)的功能。

// Requires prototype.js
function edit(action,obj) {
Element.hide(obj);
var textarea ='<div id="' + obj.id + '_editor"><input type="text" id="' + obj.id + '_edit" name="' + obj.id + '" value="' + obj.innerHTML + '" size="40">';
var button = '<input id="' + obj.id + '_save" type="button" value="SAVE" /> <input id="' + obj.id + '_cancel" type="button" value="CANCEL" /></div>';
new Insertion.After(obj,textarea+button);
Event.observe(obj.id+'_save','click',function(){saveChanges(action,obj)},false);
Event.observe(obj.id+'_cancel',function(){cleanUp(obj)},false);
$(obj.id+"_edit").focus();
$(obj.id+"_edit").select();
}

function cleanUp(obj,keepEditable) {
Element.remove(obj.id+'_editor');
Element.show(obj);
if(!keepEditable) showAsEditable(obj,true);
}

function saveChanges(action,obj) {
var new_content = escape($F(obj.id+'_edit'));

obj.innerHTML = "Saving...";
cleanUp(obj,true);

var success = function(t){editComplete(t,obj);}
var failure = function(t){editFailed(t,obj);}

var url = 'poll-ajax.PHP?a='+action;
var pars = 'id=' + obj.id + '&content=' + new_content;
var myAjax = new Ajax.Request(url,{method:'post',postBody:pars,onSuccess:success,onFailure:failure});
}

function editComplete(t,obj) {
obj.innerHTML = t.responseText;
showAsEditable(obj,true);
}

function editFailed(t,obj) {
obj.innerHTML = 'Sorry,the update Failed.';
cleanUp(obj);
}