Summary of several ways to determine whether a remote URL is valid in PHP_PHP Tutorial

Solution:
Use PHP to solve
Use the file_get_contents function, but the advantages and disadvantages are that if the url cannot be accessed, there will be a problem of terminating the program
Use curl to return, and then determine whether it is executed correctly
Use the get_headers function, according to HTTP Return the value to see if there is 200
Use js to solve:
Use the native js function ActiveXObject, only support browsers with ie core
Use jq extension
This article mainly introduces the third PHP solution , this method is rarely used, but it feels good again.

get_headers needs support

php_openssl support. Check phpinfo to see if it is enabled.
allow_url_fopen=on. Modify php.ini and run Use remote opening

function introduction:
array get_headers ( string $url [, int $format ] )

get_headers() returns an array containing the information sent by the server in response to an HTTP request header. If it fails, it returns FALSE and issues an E_WARNING level error message.

If the optional format parameter is set to 1, get_headers() will parse the corresponding information and set the key name of the array. For example:

"; 
print_r($array); 
}else{ 
echo "Invalid url resource!"; 
} 

You can see the correct return-----------------------The test is ok

Advantages and disadvantages:
Requires allow_url_fopen=on to be turned on , somewhat similar to the usage conditions of the file_get_contents function, but the return value is relatively small. You can use
function_exists to determine whether the method can be used