Article Introduction： 为什么要判断isset后还要判断empty，直接判断empty不是代码更少吗？if(isset($_SERVER['HTTP_RANGE']) && !empty($_SERVER['HTTP_RANGE'])){}------解决思路----------------------先isset是为了防止empty发警告。

2016-06-13 comment 0  937

Article Introduction：为什么要判断isset后还要判断empty，直接判断empty不是代码更少吗？

2016-06-23 comment 0  757

Article Introduction：In PHP programming, we often need to determine whether a variable has been set. This prevents programs from causing errors when using unset variables. In order to achieve this purpose, we usually use the isset() function to judge. The isset() function is used to determine whether a variable has been set and is not null. If the variable has been set and is not null, the function returns true; otherwise it returns false. Here is an example using the isset() function: $var=&q

2023-06-27 comment 0  1110

Article Introduction： php 5.4中新增加对session状态判断的功能   在以前的php 版本中,要判断session是否有效,只能用如下的方法: session_start(); if(isset($_SESSION)) { echo "Started"; } else { echo "Not Start

2016-06-13 comment 0  942

Article Introduction：This article will explain in detail how PHP determines whether a specified key exists in an array. The editor thinks it is very practical, so I share it with you as a reference. I hope you can gain something after reading this article. PHP determines whether a specified key exists in an array: In PHP, there are many ways to determine whether a specified key exists in an array: 1. Use the isset() function: isset($array["key"]) This function returns a Boolean value, true if the specified key exists, false otherwise. 2. Use array_key_exists() function: array_key_exists("key",$arr

2024-03-21 comment 0  581

Article Introduction： php 判断常量、变量、函数是否存在

2016-06-13 comment 0  742

Article Introduction： 明明上传了图片，判断图片图型时不通过。下面的代码， 我上传图片， 总是显示： 出错. 请问这个判断语句， 错了？ 请详细一些。 谢谢 if ((($_FILES['logo_file1']['type'] == "image?gif") || ($_FILES['logo_file1']['type

2016-06-13 comment 0  654

Article Introduction： 问一个判断$_POST传递参数的问题，无法取数网页上有一个新增/修改的功能，一个

2016-06-13 comment 0  909

Article Introduction：Judgment method: 1. Use the strcmp() function to judge, the syntax is "strcmp(string, specified value)", if they are equal, return 0; 2. Use the strcasecmp() function to judge, the syntax is "strcasecmp(string, specified value)" , if equal, return 0; 3. Use the "==" or "===" operator to judge, the syntax is "string == specified value" or "string === specified value".

2022-09-27 comment 0  3232

Article Introduction：This time I will bring you the operation after the interceptor determines the token invalid jump. What are the precautions after the interceptor determines the token invalid jump. The following is a practical case, let's take a look.

2018-04-16 comment 0  3207

Article Introduction：Judgment method: 1. Use hasClass() to check whether the element contains the specified class name, the syntax is "element object.hasClass("class name")"; 2. Use attr() to obtain the value of the class attribute and determine whether the attribute value is equal to the specified Class name, syntax "element object.attr("class")=="class name"".

2022-04-20 comment 0  3350

Article Introduction：php is_file determines whether the given file name is a normal file. The is_file() function checks whether the specified file name is a normal file. is_file — Tells whether the filename is a regular file Usage bool is_file ( string $filename ) $file is a required parameter

2016-07-21 comment 0  854

Article Introduction：In PHP, it is a common operation to determine whether an array contains a specified value. Sometimes we need to search an array to determine whether a certain value exists, or we need to judge whether a specified key name exists in the array, etc. This article will introduce common methods and application scenarios in PHP to determine whether an array has a specified value. ## 1. Use the in_array() function. The in_array() function is one of the functions in PHP used to determine whether a specified value exists in an array. Its syntax is: ```phpi

2023-05-11 comment 0  795

Article Introduction：PHP and JS determine the origin and jump to the specified page. Today, the editor will introduce to you a more comprehensive PHP and JS method to determine the source and jump to the specified page. I hope this method will be helpful to all students. PHP jumps according to referer: code

2016-07-13 comment 0  993

Article Introduction：The way PHP determines whether a variable is defined is: You can use the isset() function to determine. If the variable does not exist, it returns FALSE. If the variable exists and its value is NULL, it also returns FALSE. If the variable exists and its value is not NULL, it returns TURE.

2019-09-25 comment 0  7188

Article Introduction：Check whether PHP has loaded the specified extension method. In PHP, the extension method is implemented by loading the corresponding extension. Sometimes we need to confirm whether an extension has been loaded and whether it contains the methods we need. This article will introduce how to check whether PHP has loaded the specified extension method and demonstrate the method through specific code examples. Use the get_loaded_extensions function to get the list of loaded extensions PHP provides get_loaded

2024-03-27 comment 0  661

Article Introduction：How jquery determines whether it contains the specified string: 1. Use the indexOf() and lastIndexOf() methods to determine whether the string contains the specified string; 2. Use the test() method to determine whether a string matches a certain pattern.

2021-01-12 comment 0  12555

Article Introduction：加入判断语句后上传按钮失效

2016-06-20 comment 0  807

Article Introduction：在以前的php 版本中,要判断session是否有效,只能用如下的方法: session_start(); if(isset($_session)) { echo "started"; } else { echo "not started"; } 而在php 5.4(即将发行)中,对session的状态进行了细分,可以用如下的方法判断: session_st

2016-06-21 comment 0  1058

Article Introduction：PHP determines whether a certain day is before or after the specified date. There is such a requirement, the specified date is December 12th, I want to execute event A before December 12th, and event B after that. How to judge whether today is before or after December 12th? The procedure is as follows

2016-07-13 comment 0  917