php获取url中的参数

// 获取url参数值
function is_set_param($param){
$current_url = $_SERVER["QUERY_STRING"];
$arr = explode('&',$current_url);
$value = '';
foreach ($arr as $k=>$v) {
$left_c = explode('=',$v);
if ($left_c[0] == $param) {
$value = $left_c[1];
break;
}
}
return $value;
}