Graphics Reference
In-Depth Information
Figure
.
.
Time series plot of the Okayama trade area analysis system
layercontrol.html consists of checkboxes that specify whethertodisplay alayer of re-
lated information, and the
setVisibility
function is called whenan
onclick
event occurs for a check box. menu.html provides an interface such as a drop-down
menu that can be used to select the city, town or village, shopping item, and survey
year inordertoobtain therequired degreeofdependenceandthe outflow rate.Func-
tions called byevents fromthis interface aredefinedinindex.html. First,inthe script
part of index.html, an
XMLHttpRequest
object is created, as follows:
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
his object has the ability to publish HTTP requests, obtain resources and to analyze
themasXML,aswellastobuildDOMtrees,butonlythefirstoftheseabilities isused
here. In other words, the object is utilized as a simple HTTP client component. he
getResult
function receives the URL of the resource as an argument and initiates
communication between the web browser and the server that has the resource using
the
open
method of
XMLHttpRequest
.he process that occurs when the server
communication statuschangesisspecifiedinthe
onreadystatechange
method
as a function. When the data have been received in the correct way they are stored in
res
,and
res
is returned as the value of this function.
he
getDepend
function passes the URL of the CGI script (getDepend.cgi) of
the server to the
getResult
function along with a parameter that is necessary for
calculation, and then receives the IDs of the cities, towns and villages and any color
