form_checkbox([$data = ''[, $value = ''[, $checked = FALSE[, $extra = '']]]]) 
Parameters:
$data (array) – Field attributes data 
$value (string) – Field value 
$checked (bool) – Whether to mark the checkbox as being checked
 
$extra (mixed) – Extra attributes to be added to the tag either as an array or a literal string  Returns:
An HTML checkbox input tag  Return type:
string  
Lets you generate a checkbox field. Simple example:
echo form_checkbox('newsletter', 'accept', TRUE);
// Woul