print_a(mixed input [, string option_string])

The function you will use most often, prints a colorful representation of your PHP data

$option_string must be in the CSS like syntax:

e.g. "max_y:5;window:1;label:my_array"

If there is no ":" in the options string, the whole string will be used as the text for the label. new

Valid options:

return:	(0|1)	Do not print the output and instead return it as a string.
label:	(string)	Draw a fieldset/legend around the output.
max_y:	(1-n)	Maximum number of items on the same level. [...] (defaults to 50)
pickle:	(0|1)	Print a serialized representation of the array instead of printing it as a table.
export:	(0|1)	Print PHP sourcecode of the array. new
trim_tabs:	(0-n)	Trim the leading tabs in multiline strings and pad with n tabs.
window:	(string)	The output should open in a new window (javascript), the parameter is also the title for the window.
window_link:	(0|1)	Don't open a window, just print a link which opens one when clicked. new
debug_level:	(0-99)	Only do something if the debug level value is <= the global debug level ($GLOBALS['DEBUGLIB_LVL'] default 99) new
		You can also set it to an array with the levels you want to display e.g. $GLOBALS['DEBUGLIB_LVL'] = array(3,5)
avoid@:	(0|1)	If a key starts with the character "@", assume it is a recursive reference and don't follow it.
mail:	(string)	Mail the ouput as HTML mail to the supplied email address. new
mail_encoding:	(string)	encoding for the HTML mail. (defaults to "utf-8")

show_vars([string option_string])

Prints all superglobals like $_GET, $_POST, $_SESSION etc. in a big table.
Good for printing at the bottom of a page.

Options are the same as for print_a + the following options:
verbose: also show $_SERVER and $_ENV

script_runtime([bool return_mode [, string title [, string css_style]]] )

Prints the passed time since the start of the script (or the last script_runtime call) in seconds.

pre(string string [, string option_string])

Print a string so the whitespaces are visible in HTML.

option_string must be in the CSS like syntax:

eg. "r:1;trim_tabs:0;"

Possible options:

return:	(0|1)	return the output instead of printing it
trim_tabs:	(0-n)	same as in print_a()

You can disable the output of all the functions in a production environment by setting $GLOBALS['USE_DEBUGLIB'] to FALSE (e.g. trough auto_prepend in your php.ini).

And if you have to do some online debugging you can enable it again somewhere in your script by setting it to TRUE.