jQuery回调到先前定义的函数 [英] JQuery callback to previously defined function

问题描述

我仍在学习JQuery(因此使用了一些JavaScript)，但似乎无法找出如何在回调中使用先前定义的函数.

I'm still learning JQuery (and as a result a little JavaScript) but I can't seem to find out how to use a previously defined function in a callback.

说我有

<script>
$(document).ready(function() {

function ajax_start() {
                      alert("starting...");
                      }

});
</script>

我希望在另一个函数中使用它，例如:

And I wish to use this in another function e.g:

<script>
$(document).ready(function() {

$.ajax({
        beforeSend: ajax_start(),
        url: "insert_part.php",
        type:"POST",
        data: "customer="+customer
  });
});
</script>

这是正确的吗? (我认为不是，因为它不是...)进行回调的正确方法是什么?

Would this be correct? (I assume not as it doesn't...) what is the proper way of doing a callback?

推荐答案

关闭.

$(document).ready(function() {

    function ajax_start() {
        alert("starting...");
    }

    $.ajax({
        beforeSend: ajax_start, // <== remove the parens
        url: "insert_part.php",
        type:"POST",
        data: "customer="+customer // <== as Skilldrick pointed out,
                                   //     remove the trailing comma as well
    });
});

您需要这样做是因为

• ajax_start()通过执行名为ajax_start的函数求出返回的值，但是
• ajax_start评估为函数本身.

• ajax_start() evaluates to the value returned by executing the function named ajax_start, but
• ajax_start evaluates to the function itself.

我该如何在回调中包含第二个函数.类似的东西-事前发送:ajax_start，other_function(不完全是这样)?"

"how would I include a second function in the callback. Something like- beforesend: ajax_start,other_function (obv. not exactly like that)?"

有几种方法可以做到这一点.使用匿名函数将它们合并:

There are a couple ways to do it. Combine them using an anonymous function:

$.ajax({
    // if you need the arguments passed to the callback
    beforeSend: function (xhr, settings) {
        ajax_start();
        other_function();
    },
    url: "insert_part.php",
    type:"POST",
    data: "customer="+customer
});

或者只是声明一个执行所需功能的命名函数，然后使用它:

Or just declare a named function that does what you want, and then use it:

function combined_function(xhr, settings) {
    ajax_start();
    other_function();
}

$.ajax({
    beforeSend: combined_function,
    url: "insert_part.php",
    type:"POST",
    data: "customer="+customer
});

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