php-PHP全局变量的问题global

php全局变量global

代码链接:http://www.mcqyy.com/RunCode/php/#id/29b4699b9f37cc352dcf1e39c7491e86
代码:

<code> <?php $arr = array();main();array_push($arr,'2');arrSearch($arr,'2');arrSearch($arr,'1');function main(){    global $arr;    array_push($arr,'1');    arrSearch($arr,'1');}function arrSearch($arr,$el){    echo "<hr>";    echo "arr:";    print_r($arr);    echo "<br>";    echo $el.":";    if(array_search($el,$arr)){        echo 'yes';    }else{        echo 'no';    }}?></code>

结果是：
arr:Array ( [0] => 1 )
1:no
arr:Array ( [0] => 1 [1] => 2 )
2:yes
arr:Array ( [0] => 1 [1] => 2 )
1:no

ps:刚学php,还请大家指教。