<!DOCTYPE html>
<html>
    <head>
        <meta charset=utf-8>
    </head>
    <body>
        <script type="text/javascript">
        	// 补全代码
        	Number.prototype._isPrime = function(num) {
                //取平方根
                let temp = parseInt(Math.sqrt(num))
                //循环判断
                for (let i = 2; i <= temp; i++) {
                    if (num % i === 0) {
                        return false
                    }
                }
                return true
            }
        </script>
    </body>
</html>