Extron Electronics MLC 104 Plus Series - Manual (Page 140)

Special Applications, cont’d
MLC 104 Plus Series • Special Applications 5-36
PRELIMINAR
Y
Creating and using query strings
A query string is a command that contains parameters or instructions for the Web
server (the MLC) to execute. The query string is contained after the question mark
within a reference URL (Web address). (See the syntax section below.)
When a link is accessed on a Web page, the URL is sent to the Web server (MLC)
to tell it which Web page to return to the browser. Upon receiving the URL, the
MLC’s internal Web server locates the query string within the URL and executes the
command it contains.
Query string command types and syntax
Host vs. remote commands
As with SSI formatted commands, query strings can use any valid SIS command of
either type (host or remote).
• Host commands instruct the MLC, itself, to act or respond.
• Remote commands send data to an external control port on the MLC.
Command syntax
The basic format for a query string within a link is as follows:
<a href=”index.html?cmd=x”>linked text</a> where x is the SIS command
to be executed.
<a href="index.html ? cmd= "> </a>
Syntax for a URL Containing a Query String
Delimiter Delimiter
SIS command
to be executed by the
MLC (Web server)
(typed with no spaces)
HTML URL
reference (link)
command
End of link
tag
Indicator that
a command
follows
Link text
(text that appears
on the Web page for
the user to click on)
“ ?” indicates the start
of the query string.
Text between the quotation marks is typed with no spaces.