javascript - 如何改进Prototype.js回调函数代码

Question

我有这个小代码。我正在使用原型(prototype)框架，但无法将元素绑定(bind)到回调函数。这就是为什么我必须这样编写函数。

我该如何改进这段代码？

 Event.observe('firstname', 'keyup', function () {
     var form = $('customerform'),
         firstname_0 = form["firstname_0"];
     firstname.value = this.value;
 });
 Event.observe('KundeNachname', 'keyup', function () {
     var form = $('customerform'),
         lastname_0 = form["lastname_0"];
     lastname_0.value = this.value;
 });

Answer 1

每个回调之间的唯一区别是引用的表单字段的名称。我将该代码提取到一个常见的回调创建函数中:

function createHandler(fieldName) {
    return function() {
        $('customerform')[fieldName].value = this.value;
    }
}

Event.observe('firstname', 'keyup', createHandler("firstname_0"));
Event.observe('KundeNachname', 'keyup', createHandler("lastname_0"));