首先看看实例：
代码如下:
PHP
$a = "alsdflasdf;a";
$b = var_dump($a);
echo "
";
//var_dump($c);
$d=var_dump($c);
echo "
";
echo $a;
echo "
";
echo $b;
echo "
";
输出：
string(12) "alsdflasdf;a"
NULL
alsdflasdf;a
$a = "alsdflasdf;a";
$b = var_dump($a);
echo "
";
//var_dump($c);
$d=var_dump($c);
echo "
";
echo $a;
echo "
";
echo $b;
echo "
";
输出：
string(12) "alsdflasdf;a"NULL
alsdflasdf;a
