The term mobile browser refers to web browsers that are specially designed for use on mobile devices such as smartphones, tablets, PDAs or feature phones. Mobile browsers are characterized by two basic features: On the one hand, they optimize the mobile web content to be displayed on smaller display sizes and the available interaction possibilities. On the other hand, they use the computing and storage capacities of the end device as effectively as possible, as well as the available bandwidth of access to the mobile Internet. Mobile browsers are also known as microbrowsers, mini-browsers or wireless Internet browsers (WIBs).
PocketWeb, which was developed by the PDA Developer Group at TECO in Karlsruhe in 1994, is the first mobile browser. PocketWeb already used special management layers and a modified cache architecture to display HTML websites with the most effective task management and low memory usage.
Two years later, the NetHopper was released by AllPen Software for PDAs from Apple (called MessagePads) as a commercial version. Basically, this was not a stand-alone mobile browser, but it offered mobile access to the Internet: Via the mobile phone network it was possible to dial into the gateaway via which a requested resource could be loaded. Both browsers can be regarded as predecessors for modern mobile browsers.
Similar developments can be mentioned with the transfer protocols WAP and I-Mode. WAP is an intermediate step in the development of mobile browsers. Already here, an attempt was made to reduce the amount of data when displaying websites by adding a gateaway that converts the data to display. I-Mode uses the protocols and markup languages common in the WWW, such as TCP/ IP, HTTP and HTML. However, a reduced version of HTML - the so-called iHTML - has been written to enable the display of certain HTML elements on small devices.
Nowadays, mobile browsers are in most cases reduced versions of desktop versions and connected to services in the WWW via interfaces. Either variants of HTML or, in newer versions, HTML5 are used. The challenges that have arisen from the low computing and storage capacity of mobile devices and the smaller bandwidths in Internet use continue to exist and are addressed and solved by browser manufacturers in various ways.
Mobile browsers connect to the Internet by using either cellular network or wireless local area network (WLAN). As soon as a website is opened in the mobile browser, the client (browser) sends a request to the server. Depending on how the requested resource is stored and stored there, the server responds. This gives the client various information about how the resource can be displayed. There are three scenarios:
Most modern mobile browsers can handle all three variants. In some cases, so-called browser switches are used to adapt the display to the terminal device.
The mobile browser now renders the loaded data and controls the display based on the information it has received from the communication with the server. The rendering is done using a layout engine. It merges the contents, formatting and markups and renders the contents - adapted to the size of the display. It translates the HTML and CSS source code into renderable websites. There are many different browser engines: WebKit (Android Browser, Chrome and Safari), Gecko (Firefox for Mobile), Trident (IE Mobile) or Presto (Opera Mobile) are the most popular.
The graphical representation is already done by means of the Post-WIMP concept: WIMP stands for "Windows, icons, menus, pointers" and describes a specific interaction style that is characterized by clicking on elements of the graphical user interface. However, mobile browsers do not have as much storage space available, which is why newer interaction concepts are used here. This is not only because of the storage capacity, but also because of the interaction between user and browser or the end device. Examples are gesture controls with pull and wipe movements, zooming or voice commands.
A basic distinction is made between native and installable mobile browsers. Native mobile browsers are the standard programs that are pre-installed on the respective operating system. The second group, the installable mobile browsers, can be selected and downloaded by users according to their personal needs.
The wide variety of mobile browsers makes it difficult to display websites correctly on mobile devices. If you want to market a website on the mobile Internet, you therefore need detailed testing. Similar to browser tests of conventional websites, mobile websites should be checked in different browsers and mobile devices. If certain content cannot be loaded, this can adversely affect the performance of the website. The compatibility of mobile browsers with different APIs and CSS rules is a constant challenge for developers. At least the presentation in mobile standard browsers should therefore be checked or emulated. A well-known emulator is BrowserStack, for example.
In connection with the delivery of content based on information about the User Agent, there are also aspects such as crawling and indexing of mobile websites. In addition to the optimized display for different browsers and end devices, the correct readout of mobile websites by search engine crawlers depends on the information about the user agent. Usually, lists of user agent strings are used here to enable the crawlers to compare the user agent of the respective device with the possible user agent strings (for example, new devices).10] If incorrect or incomplete information is given here, this can lead to crawling errors and in the worst case to the de-indexing of the mobile website.