<!DOCTYPE html>
<html>
    <head>
        <meta charset=utf-8>
    </head>
    <body>
        <script type="text/javascript">
        	// 补全代码
        	Number.prototype._isPrime=function(){
                for(let i=2;i<this;i++){
                    if(this%i==0) return false
                }
                return true
            }

        </script>
    </body>
</html>