PHP判断网址是否合法的正则表达式

<script>ec(2);</script>

//一

'/^https教程//?.+.[a-z]{2,4}$/';

//

'/^https//?.+.[a-z]{2,4}/.*$/';

//

'/^https?://.+.[a-z]{2,4}/.*$/';

//

'/^https?://.+.[a-z]{2,4}(/.*|)$/i'

//
/^http(s)?://([a-za-z0-9.]?([0-9a-za-z][0-9a-za-z-]+.)+[a-za-z]{2,5})|((25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]).(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0).(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0).(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9]))/

//
filter_var($url, filter_validate_url)