PHP Functions Essential Reference

decbin

string decbin(int dec) 

Returns the binary representation of the specified decimal integer argument.

Returns:

String binary representation of an integer

Description:

Converts a decimal number into a string containing its binary representation. The largest decimal value that can be converted is 2147483647. If you have to deal with larger numbers, you need to write a custom function to handle the values.

Version:

PHP 3, PHP 4

See also:

base_convert() 
bindec() 
dechex() 
hexdec() 
decoct() 
octdec() 

Example:

Get the binary representation of an integer

$number = 42; echo "The binary of $number is ", decbin($number);