php全角数字转为半角数字

php把全角数字转为半角数字的函数

<?
function GetAlabNum($fnum){
 $nums = array("０","１","２","３","４","５","６","７","８","９");
 $fnums = "0123456789";
         for($i=0;$i<=9;$i++) $fnum = str_replace($nums[$i],$fnums[$i],$fnum); 
 $fnum = ereg_replace("[^0-9.]|^0{1,}","",$fnum);
         if($fnum=="") $fnum=0;
         return $fnum;
 }
?>