找不到 Javascript 函数

Question

我在 document.ready() 中有以下代码

if ($("#site-master").length > 0) {

    setMinContentHeight();

    function setMinContentHeight() {

        // removed for clarity
    }
}

我只是检查页面是否正确 (#site-master)，然后调用我的最小高度函数，但是我在 firebug 中收到以下错误:ReferenceError: setMinContentHeight is not defined。

我不是 JavaScript 专家，但这怎么可能呢？如果我将它移到 document.ready() 之外，该函数就可以工作。我检查了一下，if语句里面的代码到了。

此外，这是实现我想要的目标的最佳方式吗？

提前致谢。

Answer 1

永远不要在if 或for 语句中声明您的函数:

function setMinContentHeight() {
    // removed for clarity
}

if ($("#site-master").length > 0) {
    setMinContentHeight();
}

如果我们解决 ECMAScript specification , 根据 Chapter 12 , if 子句被认为是一个语句(以及for、while、with、try/catch 等)。

因此，遵循语义部分的注意:

Several widely used implementations of ECMAScript are known to support the use of FunctionDeclaration as a Statement. However there are significant and irreconcilable variations among the implementations in the semantics applied to such FunctionDeclarations. Because of these irreconcilable differences, the use of a FunctionDeclaration as a Statement results in code that is not reliably portable among implementations. It is recommended that ECMAScript implementations either disallow this usage of FunctionDeclaration or issue a warning when such a usage is encountered. Future editions of ECMAScript may define alternative portable means for declaring functions in a Statement context.

这意味着我们不能保证在这种情况下的行为一致，因此，如果在 语句.