Just because of the sheer numbers of new sites coming online each day, there are bound to be a large percentage that have problems. A common scenario is that one person builds the site for you or you build it yourself. That person uses a single browser to examine the results of their efforts. Often, these are people who are not programmers by profession, and indeed that is good. The tools of today can make it possible for almost anyone to design a good web site. The drawback is that when you use these tools, you are generating software code. In almost any software development project, a minimum of 15% (and often up to 30% or 40%) of the budget goes for testing of the product at various stages. Since web sites are often a do it yourself proposition, you do not see the need for fully testing what you have created. Indeed, you may fall into the "trap" of many software developers and get defensive about the prospect of something being wrong with your software.
 

When any testing is done on a site, it is usually what is known as positive testing. That means that you check only those things that you would normally expect to have happen. This approach only works if every visitor to your site only does those things that you expect them to do. Through years of experience testing software, I have learned that users often do the totally unexpected.
 

Develop a plan to test your software. This doesn't have to be anything fancy, but do write it down. Start by going to each page and determining each action a user can take. Don't assume that they will enter only what you expect. For example, if you have a field on your site for a user to enter the number of children they have, you need to see what happens if they put in "three" instead of "3". How many characters will that field accept; fill it with that number of numbers and characters. These are separate tests that you should note in you test plan. If you have any calculations in your site, you need to be especially vigilant in making sure these calculate correctly, even when the unexpected is entered. Remember, computers do not like it when you divide by zero.

Include a link test. You should determine if your site has any links that do not work correctly. This is commonly done during the positive testing that most people do, but in case you didn't, add it to your test plan. Actually send mail on those mailto links to ensure it gets there. Check each link by actually using it.

You also need to determine how your site will look (and indeed whether it will even work) with various browsers. You do not need to own every version of every browser to ensure compatibility. This can be done easily and economically using some of the resources that already exist on the net.

Make sure that your site includes a webmaster@yourname.com link so that if visitors find problems with your site, they can advise you of it. Some of the best feedback comes from customers. Unfortunately, most people will just go to another site if they have problems, rather than send you this email to let you know they encountered a problem. The key is to make your site professional from the start. That starts with building quality in as you develop your site. To do that, you need to have a good test plan and execute it thoroughly.