Web Services & Online Applications

In this course, we were introduced to the basics of HTML, CSS and JavaScript. With the help of these elements, amazing web services and online applications can be created. One very important part of the course was the introduction to the HTML DOM (document object model) as this is the fundamental link between the tag-based structure of a html-webpage and the functionality of JavaScript. JavaScript is a leight-weight and easy to learn scripting language which is directly executed within a web-browser. The examples in this chapter give an idea how the linkage between a webpage and JavaScript works.


Example:

The following example demonstrates how a user-input can be processed within an application programming interface (API) and by making use if the HTL DOM. This example uses the OpenLayers API with an Open Street Map as base layer. You can insert latitude and longitude values in the corresponding text boxes and a marker at the given position will be drawn. The reset-buttom will delete the markers and center the map to Salzburg again.

Description

You can enter latitude and longitude values in the textboxes below. Within a JavaScript file the degree, minutes & seconds notation will be changed to decimal degree for processing. If you do not enter any value, it will be considered zero.


Latitude
deg
(0°-90°)		 min
(0'-60')		 sec
(0''-60'')		 North / South
N S

Longitude
deg
(0°-180°)		 min
(0'-60')		 sec
(0''-60'')		 East / West
E W