If the web development company is not correct, the user (often a potential client) will go. Items such as formatting can check; for example, the text is of uniform size and color and that there are no typos on the website.

We can also check the alignment of text and any pictures to make sure a consistent look and feel on the website. Also, websites color-scheme can immediately determine whether or not the user is going to stay and look at the site.

The first thing that comes to mind when thinking about the security of a website is when having the deal with credit cards web development services.

But, most credit card processing services will give a pre-built tool for dealing with credit card details, and this is often passed over to that website designing company.   
Still, various web designing company include forms for a user to fill in, which can then be collected on the site somewhere or in an external database. A website testing company should consider consideration carefully, and sequential testing should be performed to make sure that somebody can't get access to this information.

Browser Compatibility
In the past, virtually everybody used Internet Explorer. Now, internet users have an option such as handling, Internet Explorer, Firefox, and Safari for Macs, etc. An example of this is how Firefox and IE handle 'white space,' making a web designing servicesappear entirely different on every browser.Hence, a website must be tested on at least IE and Firefox(currently the most popular browsers) to make sure most types of test coverage before a site goes live.