php函数：判断字符编码的简单方法

3. function chkbm($string){
4. $bm = array(ASCII, GBK, UTF-8);
6. foreach($bm as $c){
7. if( $string === iconv(UTF-8, $c, iconv($c, UTF-8, $string))){//转换编码后是不是相等
8. return $c;
9. }
10. }
11. return null;
12. }
13. ?>