Is there a way to test my website for security holes?

I have a couple of websites. Is there a way to test and check my websites in case they are hackable or have security holes etc?

Cheers.

 

Here you go: http://www.techsupportalert.com/con...d.htm?page=0,10#Check-website-vulnerabilities

 

Thank you.

 

OWASP is "the open web application security project". It's whole mission is to secure all the web apps out there in the world. In particular they maintain a list of the top 10 web app vulnerabilities and give some guidance how to avoid them.

https://www.owasp.org/index.php/Top_10_2010-Main