<html> <head> <title>untitled</title> </head> <body> <?php $in="2344"; if(ereg("^(-{0,1}|\+{0,1})[0-9]+(\.{0,1}[0-9]+)$",$in)) echo "ok!"; else echo "sorry,please input again!"; ?> <br>很简单的嘛! </body> </html>