diff --git a/htdocs/core/lib/ajax.lib.php b/htdocs/core/lib/ajax.lib.php
index 130394b75a2..f91ec3d188d 100644
--- a/htdocs/core/lib/ajax.lib.php
+++ b/htdocs/core/lib/ajax.lib.php
@@ -31,7 +31,7 @@
  *
  *  @param	string	$selected           Preselecte value
  *	@param	string	$htmlname           HTML name of input field
- *	@param	string	$url                Url for request: /chemin/fichier.php
+ *	@param	string	$url                Url for request: /path/page.php. Must return a json array ('key'=>id, 'value'=>String shown into input field once selected, 'label'=>String shown into combo list)
  *  @param	string	$urloption			More parameters on URL request
  *  @param	int		$minLength			Minimum number of chars to trigger that Ajax search
  *  @param	int		$autoselect			Automatic selection if just one value