PHP中global，$GLOBALS的比较

一直对这两个变量比较迷惑，今天写了一个程序，测试了一下，总算明白了。

    代码：

 <?php$GLOBALS['test'] = "i am valid.";
function testFun1(){ echo "i am in testFun1().<br/>";
    echo '$GLOBALS is '.$GLOBALS['test'].'<br/>';
 unset($GLOBALS['test']); echo '$GLOBALS is '.$GLOBALS['test'].'<br/>';}
function testFun2(){ echo "i am in testFun2().".'<br/>';    global $test;
 $test = "changed";  echo '$GLOBALS is '.$GLOBALS['test'].'<br/>';
 unset($test);
 echo "global test is ".$test.'<br/>';  echo '$GLOBALS is '.$GLOBALS['test'].'<br/>';}
testFun1();testFun2();?>

结果：

i am in testFun1().$GLOBALS is i am valid.$GLOBALS is i am in testFun2().$GLOBALS is changedglobal test is $GLOBALS is changed 

引用他人的一句话：

也就是说global $var其实就是$var = &$GLOBALS['var']。调用外部变量的一个别名而已。