PHP variable names are case sensitive, and function names are case insensitive

PHP variable names are case-sensitive. function names are case-insensitive and are often ignored by new users. test the following. PHP variable names are case-sensitive: & amp; lt ;? Php $ aaa = & quot; phpddt.com & quot; $ AA

PHP variable names are case-sensitive. function names are case-insensitive and are often ignored by new users. the test is as follows.

PHP variable name case sensitive test:

PHP function name case-insensitive test:

The above code will report an error :(! ) Fatal error: Cannot redeclare BBB ()