jQuery isFunction检查错误“函数未定义” [英] jQuery isFunction check error "function is not defined"
问题描述
在试图运行它之前,我想检查函数是否存在。这里是我的代码:
$ $ p $ $ code if($ .isFunction(myfunc())){
console.log(函数存在,运行!!!);
}
但是,当函数不可用时,我得到错误:
myfunc未定义
我该怎么办检测?这是我的工作测试: http://jsfiddle.net/3m3Y3/
相反,您应该只使用函数名称而不运行它:
if($ .isFunction(myfunc)){
然而 - If myfunc
不是一个函数,也不是任何其他已定义的变量,但它仍然会返回一个错误,尽管它是不同的。像 myfunc没有定义
。
您应该检查名称是否存在,然后检查它是否为函数,像这样:
if(typeof myfunc!=='undefined'&& $ .is.Function(myfunc)){
工作示例: http://jsfiddle.net/sXV6w/
I want to do a check whether a function exist or not before trying to run it. Here is my code:
if ($.isFunction(myfunc())) {
console.log("function exist, run it!!!");
}
However, when the function is not available I got the error:
myfunc is not defined
How can I do the detection? Here is my working test: http://jsfiddle.net/3m3Y3/
By putting ()
after the function name, you're actually trying to run it right there in your first line.
Instead, you should just use the function name without running it:
if ($.isFunction(myfunc)) {
However - If myfunc
is not a function and is not any other defined variable, this will still return an error, although a different one. Something like myfunc is not defined
.
You should check that the name exists, and then check that it's a function, like this:
if (typeof myfunc !== 'undefined' && $.isFunction(myfunc)) {
Working example here: http://jsfiddle.net/sXV6w/
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