diff --git a/include/ac_common.php b/include/ac_common.php
index 8668504e1..cfc85f85d 100644
--- a/include/ac_common.php
+++ b/include/ac_common.php
@@ -77,13 +77,13 @@ function cmpDate ($p_date,$p_date_oth) {
  */
 function isNumber($p_int) {
   if ( strlen (trim($p_int)) == 0 ) return 0;
-  $p_int=trim($p_int);
-  $p_int=FormatString($p_int);
-  if (! ereg ("^-{0,1}[0-9]+.{0,1}[0-9]*$",$p_int) ) {
-    return 0;
-  } else {
+
+  if ( (string) $p_int === (string) (int) $p_int ) 
     return 1;
-  }// !ereg
+  else
+    return 0;
+
+
 }
 
 /*!