Isset Empty Php

Isset (unknown) isset---&http://www.aliyun.com/zixun/aggregation/37954.html ">nbsp; Determine whether the variable set syntax: int isset (mixed Var); Note: Returns true if the parameter var exists, or returns false. Example: <?php $ ...

The difference between 1.echo and print echo and print in PHP basically the same function (output), but there are still some nuances between the two. echo output does not return a value, but print returns the value, when its implementation fails to return flase. Therefore, it can be used as a normal function. For example, after executing the following code, the value of variable $ r will be 1. Copy PHP content to the clipboard PHP code: $ r = print "Hello World"; This means print ...

It would be faster to enclose the string in single quotes instead of double quotes. Because PHP searches for variables in double-quoted strings, single quotes do not. Note that only echo can do this: it's a "function" that takes multiple strings as arguments, Echo is a language structure, not a real function, so the function with double quotes). 1, if you can define the class method as static, as far as the definition of static, it will speed up nearly 4 times. 2, $ row ['id'] speed ...

php tutorial email spam (phpmailer send qq mail) * @ author ray * @ since 2009-08-07 smtp mail account must be more, otherwise it will be qq server as spam. 2. Appropriate dormancy smtp.dat file format for smtp.163.com | sss@163.com | password smtp.sina.com | www@sina.com | password www.jzread.com program randomly selected a connection. ..

Fourteen make PHP beginners a big headache Summary Today for everyone to give PHP beginners a headache big summary, the following 14 questions hope for PHP beginners to help. 1, the page can not be passed variables get, post, session Automatic global variables in the latest php version is turned off, so to get over the variables from the previous page to use $ _GET ['foo'], $ _ POST [ 'foo'], $ _ SESSION ['foo']. Of course it can be ...

<?php/** * Send QQ mail via Phpmailer * @author Ray * @since 2009-08-07 * * Define (' __debug__ ', false); Define (' __psw_file__ ', DirName (__file__). '/smtp.dat '); Define (' Sleeping_email ', dirname (__file__) ....

delete the data value of this paragraph is to delete a data code is based on a user url address bar passed parameters, go to the mysql database to delete the operation of the tutorial Oh. / $ host = 'localhost' ; $ user_name = 'root'; $ password = 'admin'; $ conn = mysql_connect ($ host, $ user_name, $ password); ...

When we write the file upload code, we also need to consider an important realization of the function, that is, the progress of the required file upload. Currently I know PHP file upload progress bar in two ways, one is to use APC extension module written by PHP founder Rasmus Lerdorf to achieve, the other method is to use PECL extension module uploadprogress achieve. PHP-based application-specific AJAX analysis PHP restrictions on the specific size of the file upload solution PHP batch upload pictures of the specific implementation of the ...

Empty (unknown) empty---&http://www.aliyun.com/zixun/aggregation/37954.html ">nbsp; Determine whether the variable set syntax: int empty (mixed Var); Note: If the variable exists and has a set variable value return FALSE, otherwise return true. Example: <?php &nb ...

php tutorial image upload code (with thumbnails and add watermarking function) This picture upload source code is a can upload pictures and also has to upload images generated thumbnails and watermarking Oh, can be said to be a perfect Image upload category Oh. class upfile {public $ filepath = "www.jzread.com/"; / / upload files stored in the folder public $ filesize = 10 ...