# for
~~~
<?php
for ($x=0; $x<=10; $x++) {
echo "数字是：$x <br>";
}
?>
~~~
# foreach
每进行一次循环迭代，当前数组元素的值就会被赋值给 $value 变量，
并且数组指针会逐一地移动，直到到达最后一个数组元素。
<?php
$colors = array("red","green","blue","yellow");
foreach ($colors as $value) {
echo "$value <br>";
}
?>
