Mercury: Venus: Earth: Mars: Jupiter: Saturn: Uranus: Neptune: Pluto:
Explanation of Web Page Functionality
The aforementioned request string is sent off to a PHP-based Web Service. If this Web Service receives a correctly-formatted request string, it responds with an HTTP header of ‘200 OK’ and a succession of declarative, statistical statements relating to the selected planet. Following the usual grammatical convention, a ‘period’/’full stop’ and a ‘space’ separates the sentences. In this example, the background colour of the paragraph is set to ‘khaki’ and the sentences are displayed in a bullet-pointed list.
If this Web Service receives an incorrectly-formatted request string, it responds with an HTTP header of ‘400 Bad Request’ and a paragraph of text that explains the expected request string format. You can test this response by clicking the ‘Send XMLHttpRequest’ button without selecting a planet; the explanatory paragraph will be displayed above.
The Web Service will only respond with either a ‘200 OK’ or ‘400 Bad Request’ HTTP header. For all other communication issues – for example, a loss of internet connection – an error message will be displayed in red font, informing the user that an ‘unforeseen communication issue’ has occurred.