Posts tagged "rendering differences"

Why Does My Page Look Different In BrowserLab?

Does Your Page Look Different In BrowserLab?

In a recent blog post we covered some reasons why you might see rendering inconsistencies in BrowserLab when looking at screenshots from Internet Explorer 9.  Now let’s take a look at why you might see some cross-browser testing differences between the way BrowserLab’s screenshots display your page versus how your page looks on a local machine.  If you’ve run into a situation where the screenshot from BrowserLab doesn’t square up with what you see locally in the exact same browser, there are a few known culprits.

Resource Availability

If you’re seeing major rendering differences, such as missing images or stylesheets, make sure that the resources you are referencing in your page are available to BrowserLab.  Start by increasing the Delay setting in BrowserLab, to give the resources a little more time to load. Make sure you aren’t referencing resources that you have installed locally or are only visible from inside your network.  If you are in doubt, ask a friend who is outside your own network to take a look at your page.  If your friend can’t see the missing resources, BrowserLab won’t be able to either.  If you need BrowserLab to be able to see content inside your network, you may want to take a look at this article about Egress IPs or use one of our options for testing local content.

Screen Resolution

The screenshots you get back from BrowserLab have all been rendered on browsers sized to 1024×768. If you are looking at the page on a browser that’s sized either larger or smaller, you could see some layout differences.  Try resizing your browser to 1024×768 and reload.  The very popular Web Developer add-on for Firefox has a tool to do this easily.

Browser Chrome

This one is really an extension of the same problem described above.  If you have installed any toolbars (like the Web Developer add-on suggested above), or if you are using a browser theme that changes the size of the borders, buttons and other chrome around the browser, you may get slight changes in window size, which could make the screenshot look different.  You’re most likely to run into this if you have multiple toolbars installed and are seeing vertical sizing or spacing issues.

Different or Missing Fonts

We try to keep our browsers as close to their default installation as possible.  This also means we have not installed any fonts beyond what ships with the OS.  If you are seeing font discrepancies, this may be behind them.  Consider using Web Fonts, as described in a previous blog post.

Browser and/or System Settings

If you have changed certain default settings on any of your browsers or in your OS, then it’s possible that you may run into subtle rendering differences.  A good example of this is the ClearType font smoothing setting in Windows.  If you’ve turned off font smoothing on Windows, you may see some differences in font rendering.  But more generally, remember one of our main philosophies: to try and keep our browsers as close to a default install as possible.

Operating System Differences

Remember that font smoothing issue from above?  ClearType font smoothing is on by default in Windows XP and higher, but not in Windows 2003.   It’s not practical for us to serve screenshots from every permutation of the various browsers and operating systems that are available.  We’ve tried to provide an experience that represents what a typical user may have installed, but you may find small rendering differences between OS versions, and even OS patch levels.

 

If you are seeing screenshot discrepancies that cannot be explained by any of the above causes, we’d love to hear about them!  Consider coming over to the BrowserLab User Forum and letting us know about the problem you’re seeing.

Duane O’Brien
BrowserLab Engineer