問題描述

我正在使用 jQuery 1.5 版.我在看 jQuery 的 change() 函數特別是在這一點:

I'm using jQuery version 1.5. I am looking at jQuery's change() function and specifically at this bit:

.change( [ eventData ], handler(eventObject) )
eventData: A map of data that will be passed to the event handler.
handler(eventObject): A function to execute each time the event is triggered.

JavaScript 中的數據映射"到底是什么?如何使用以下測試函數作為事件處理程序?

What exactly is a "map of data" in JavaScript? How can I use the following test function as an event handler?

var myHandler = function(msg){alert(msg);};

我試過了:

$("select#test").change(["ok"], myHandler);

并且警報報告 [object Object]

and the alert reports [object Object]

推薦答案

參見event.data.數據不會作為參數傳遞給處理程序，而是作為事件對象的屬性:

See event.data. The data is not passed as argument to handler, but as property of the event object:

$("select#test").change({msg: "ok"},  function(event) {
    alert(event.data.msg);
});

處理程序始終只接受一個參數，即 event 對象.這就是您的警報顯示 "[object Object]" 的原因，您的函數正在打印事件對象.
如果你想使用帶有自定義參數的函數，你必須將它們包裝到另一個函數中:

The handler always only accepts one argument, which is the event object. This is the reason why your alert shows "[object Object]", your function is printing the event object.
If you want to use functions with custom arguments, you have to wrap them into another function:

$("select#test").change({msg: "ok"},  function(event) {
    myHandler(event.data.msg);
});

或者只是

$("select#test").change(function(event) {
    myHandler("ok");
});

<小時>

順便說一句.選擇器最好寫成 $('#test').ID 是(應該)唯一的.無需在標簽名稱前添加.

Btw. the selector is better written as $('#test'). IDs are (should be) unique. There is no need to prepend the tag name.

這篇關于如何使用帶有 jQ??uery 的 change() 方法的參數的函數?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！