aspx, getting the
values of A and B, and writing the sum to the response buffer. When the XMLHttpRequest
object receives the response from Default2.aspx, it calls the doUpdate function, which
checks to see if the value of the readyState property is equal to ???4,??? indicating that the
request has been completed. If the value is equal to ???4,??? the function updates the
INPUT field named TOT with the value returned by Default2.aspx, which is stored in the
XMLHttpRequest object??™s responseText property.
Summary
In this chapter, you were given a brief history of the methodologies of building user
interfaces that send data to servers for processing and the constantly swinging pendulum
from thin client to fat client. You were brought up-to-date on what the newest trend in
this development is??”web-based thin clients with rich functionality??”thanks to the asynchrony
delivered by the XMLHttpRequest object, which is the core of AJAX. You then built a
simple example that demonstrated how it works. This example was very basic and barely
scratched the surface of what can be done with AJAX.
Pages:
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59