How can a function within a function call a variable of the parent function?

var_dump(function_exists('b')); // false function a(){     $var = 123;     function b(){      &nb

喵~ 2022-12-05 19:48:12 0  0  655

function function function

The teacher told me where to find the functions provided by WeChat?

小李飞刀 2018-05-14 21:27:13 0  2  1188

Calling a function without using print(function()) format? ?

Calling a function without using print(function()) format? ? Can direct functions (parameters) be used?

力 2020-07-23 00:07:01 0  1  1329

javascript - Questions about function closures and passing functions as parameters

1. Description: I want to get a function array result. First, the func function adds an anonymous function to the array result (each anonymous function saves its own num). But I pass in the anonymous function after return with parameters, which is equivalent to just It's just a replacement, why are ...

世界只因有你 2017-06-26 10:50:31 0  3  855

javascript - Problem with function parameter default value being function in ES6?

I have a lot of confusion about the situation where the default value of a function parameter is a function, such as {code...} According to Ruan Yifeng's es6 introduction, I know that if the function parameter is a default value, there will be a block-level scope wrapping the parameter first, and af...

阿神 2017-07-05 11:09:13 0  4  1337

mysqli function

When using mysqli_num_rows() and other functions in the TP5.1 framework, an error will be reported. Can these functions not be used on TP?

林瑞程 2019-09-07 21:00:50 0  5  1404

functionunset()

The tutorial says: 3. Use the function unset() to destroy the variable, but the code demonstration uses var_dump(); are unset() and var_dump() the same function? Address: //m.sbmmt.com /code/985.html

Rebecca 2022-10-19 11:04:45 0  1  1498

javascript - What is the difference between a callback function and a normal calling function?

The definition of a callback function is to pass function b as a parameter to a for execution. At this time, b is the callback function. I suddenly have a question, what is the difference between it and calling b directly in function a? I wrote a demo myself {code...} It takes about 3 seconds to see...

欧阳克 2017-06-26 10:53:07 0  2  1440

PHP nested function and anonymous function scope issues

{Code...} All functions and classes in PHP have global scope and can be defined within a function and called outside it, and vice versa. Why can function b obtain the local variables of function a by passing parameters? {Code...} Similarly, why does the anonymous function also obtain external variab...

phpcn_u1582 2017-05-18 10:45:34 0  1  657

javascript - What is the difference between a line of code placed inside a function and outside a function?

//Inside function {code...} //Outside function {code...} Why?

我想大声告诉你 2017-06-28 09:22:31 0  1  786

javascript - How does the callback function access the value under the current function?

I defined an array variable in the function, which contains 6 elements, and then called the callback function in the function. The value of the array variable cannot be accessed in the callback function, but the length attribute can be accessed. I feel very confused and don't know how to solve it. {...

大家讲道理 2017-05-16 13:35:48 0  4  587

What is the difference between functions and variables?

What is the difference between functions and variables? Why appear together? Functions and variables, all of them are faint.

武汉蜗牛 - Jack Li 2019-09-08 11:38:24 0  8  2502

Are these methods still useful? The execute() method seems to be unable to obtain data

Are these parameter binding methods still in use? The execute() method seems to be unable to obtain data

成大事者不纠结 2021-10-24 12:54:29 0  4  729

Using JavaScript function calls

I want to call a JS function from Swift and I want to get the result of the JS in Swift. I have a lot of functions that need to be called from Swift. These functions may or may not contain parameters. You also need to include a closure for the result.

P粉118698740 2023-08-15 17:25:19 0  1  578

javascript - Encapsulate the repeated parts of these two functions into one function?

{Code...} The two functions are very similar (repeated). How to encapsulate the repeated parts of these two functions into one function?

大家讲道理 2017-05-19 10:09:46 0  3  666

There is no main function in javascript

There is no main function in javascript. The main function is often used in Java and C languages. It is also called the main function and is required to have a return value. Returning 0 means that the program is successfully executed normally, and returning a non-0 value means that the program ends ...

手机用户757625696 2022-04-06 13:51:04 0  0  1198

javascript - How to bind a callback function to a variable

Can Javascript bind a callback function to a variable? That is: when the value of this variable changes, the callback function is triggered and the content in the callback function is executed.

高洛峰 2017-06-26 10:53:29 0  3  940

PHP substr() function

How to understand the usage of PHP substr() function: If the start parameter is a negative number and length is less than or equal to start, then length is 0. This sentence

ringa_lee 2017-05-24 11:30:51 0  2  818

function

If you declare a function say(); and then var a = say; is the address or value of say passed to a at this time?

巅峰之前 2019-09-17 09:35:44 0  2  1299

What is the difference between directly assigning a function to a variable and referencing a function?

What is the difference between directly assigning a function to a variable and referencing a function? For example: Fragment 1 and Fragment 2 Fragment 1 {Code...} Fragment 2 {Code...} The function in onclick in Fragment 1 allows access to the variables in fn, but the onclick function in Fragment 2 d...

大家讲道理 2017-05-19 10:33:08 0  2  566