PHP urlencode Function: Usage, Parameters, and Examples

The urlencode() function converts predefined characters in a string to HTML entities suitable for URL query strings, encoding spaces as plus signs and non‑alphanumeric characters as percent‑encoded values.

Parameter: $str – the string to be encoded.

Return value: A string where all characters except -_. are replaced with % followed by two hexadecimal digits; spaces become +.

Example 1: Encoding a simple string containing both English and Chinese characters.

<?php
$userinput = "hello 你好";
echo '<a href="mycgi?foo=' . urlencode($userinput) . '">';
?>

Output: href="mycgi?foo=hello+%E4%BD%A0%E5%A5%BD"> Example 2: Encoding multiple query parameters and safely outputting them with htmlentities().

<?php
$foo = "hello";
$bar = "weorld";
$query_string = 'foo=' . urlencode($foo) . '&bar=' . urlencode($bar);
echo '<a href="mycgi?' . htmlentities($query_string) . '">';
?>

Output:

<a href="mycgi?foo=hello&bar=weorld">