Effects of Ctrl+MouseWheel


Tip: If you have the Microsoft Intellimouse or compatible "wheel" mouse, you can change the settings very easily by pressing the Ctrl key and rolling the wheel on the mouse.  Initially, Internet Explorer offered this feature. Over time the other browsers introduced the same capability. Some required altering default settings to have the feature (e.g., Mozilla Browser). As the feature caught on with other browsers, it became part of the standard feature (built in for use initially without having to alter default settings).

Internet Explorer chose to increase the text size when the MouseWheel was rolled down. Firefox followed suit and did the same (rolling down increased text size). As other browsers implemented the feature, some decided IE was wrong, and they chose to decrease text size when the MouseWheel was rolled down, increasing when the MouseWheel was rolled up (e.g., Opera). Over time, Internet Explorer decided to reverse (e.g., IE 7 switches to the same as the Opera Browser). Starting with Firefox version 3.0 (beta version), they too switched, but when the final version was released, the mouse wheel feature seemed to have disappeared, at least in Windows 7, and probably in Vista.

Internet Explorer not only increased the text size but it also increased the entire layout (effectively called "Zoom"). Depending on the design of the web page and the width of your monitor affects whether something is gained or lost. Some web page designs are a fixed width and for larger monitors (higher resolutions), the design will be centered or at the left side of the screen. Other web page designs expand to fill the available space, regardless of resolution or width. For web page designs that filled the available space, the entire web page would no longer be visible when the layout was increased in size (caused a horizontal scrool bar to show up). Several other browsers (e.g., Firefox and Mozilla) choose to affect text size only, which is what is desired in many cases (i.e., make text larger and easier to read). In web page designs that have fixed size containers, the text inside those containers could increase but there not be enough room to caontain all of hte text, therefore, increasing the text size beyond a certain point causes the last portions of text to not be visible. In these cases, IE would win out because it increased everything (zoom). Starting with Firefox 3.0, the default action is to increase text size and layout (zoom), the same as Internet Explorer had done all alone. Firefox 3.0 also does have an option to increase text size only (available in the View Text Size options). This method allows either method to be used. Hopefully, IE and the others will follow suite. The only problem now is that it seems Firefox has dropped allowing the mouse wheel to control the zoom or text size.

Other browsers

There are a lot of browsers out there besides the major most common known browsers. The rendering of a page code is often based on the base code of another major browser. For example, Maxthon Browser is a browser that uses Internet Explorer's Layout Engine (Trident Layout Engine) to display a page. Some of these types of browsers require Internet Explorer to be installed to use their browser. Other browsers supply all needed code to ensure a clean install so no additional browser need to be installed. When a browser's layout code is based on another major browser code base, very often they adapt the same method to affect what the Ctrl+MouseWheel does to the displayed page.

The Mozilla browser (now retired) was once the leading alternative to Internet Explorer and Netscape. Netscape (as part of AOL) decided to donate their code to the Mozilla Foundation. Around that time, the Mozilla Foundation started development of a new browser, which ended up being the Firefox Browser. The code base for the Mozilla/Netscape/Firefox layout engine is called the Gecko Layout Engine. Since the Mozilla Foundation code is Open Source, several different browsers have been developed that use the basic Gecko code base.

Some broswers use the layout code base of Trident and Gecko (e.g., Maxthon).

Due to the different methods implemented over time, I started collecting the data into a grid that might be helpful to the curious.

Effects of Ctrl+MouseWheel Up

Browser Layout Engine Ver. Text Size Page Layout
Internet Explorer IE 6 (and lower) Trident   Decrease Decrease
Internet Explorer IE 7 Trident   Increase Increase
Opera Opera Presto 9 and under Increase Increase
Opera Opera Presto 10 Alpha Increase Remains Same
Opera Opera Blink 10+ Increase Remains Same
Mozilla Mozilla (discontinued) Gecko all Decrease Remains Same
Firefox Firefox Gecko 1 & 2 Decrease Remains Same
Firefox Firefox 3 Gecko 3.0 Increase Increase or Remain same (user's choice)
K-Meleon K-Meleon Gecko   Decrease Remains Same
Netscape Netscape (discontinued) Gecko 7 and under Decrease Remains Same
Netscape Netscape (discontinued) Trident and Gecko 8 Decrease Remains Same
Flock Flock (discontinued) Gecko 1.2 Increase Remains Same
Flock Flock (discontinued) Gecko 2.0 Beta Increase Increase or Remain same (user's choice)
Flashpeak Slimbrowser Flashpeak Slimbrowser Trident 4.10 Increase Remains the same
Maxthon Maxthon Trident   Increase Increase
Avant Avant Trident   Increase Increase
Safari Safari KHTML   Increase Increase
SeaMonkey SeaMonkey Gecko   Decrease Remains Same
Camino Camino (discontinued) Gecko   Decrease Remains Same

Trident Layout Engine (Internet Explorer) Based Browsers

Browser Layout Engine Ver. Text Size Page Layout
Internet Explorer IE 6 (and lower) Trident   Decrease Decrease
Internet Explorer IE 7 Trident   Increase Increase
Flashpeak Slimbrowser Flashpeak Slimbrowser Trident 4.10 Increase Remains the same
Maxthon Maxthon Trident   Increase Increase
Avant Avant Trident   Increase Increase

Gecko Layout Engine (Mozilla Foundation) Powered Browsers

Browser Layout Engine Ver. Text Size Page Layout
Mozilla Mozilla (discontinued) Gecko all Decrease Remains Same
Firefox Firefox Gecko 1 & 2 Decrease Remains Same
Firefox Firefox 3 Gecko 3.0 Increase Increase or Remain same (user's choice)
Flock Flock (discontinued) Gecko   Increase Remains Same
Netscape Netscape (discontinued) Gecko 6 to 9 Decrease Remains Same
K-Meleon K-Meleon Gecko   Decrease Remains Same


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