求高手解析个php题目
<?php
$arr = array(0 =>1,'aa' => 2,3,4);
foreach($arr as $key => $val){
echo "key:".$key.",jisuan:";
print($key == 'aa' ? 5 : $val);
echo "<br>";
}
?>
var tmp = 'a';
if([] == false) tmp += 'b';//这里的[]是啥,数组吗
if(![]) tmp += 'c';//这里的[]是啥,数组吗
alert(tmp); //tmp 值为 ?
A.a
B.ab
C.ac
D.abc