Echelon i.LON 1000, Руководство пользователя

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i .LON 1000 Internet Server User’s Guide 9-13
<form action="outputs.htm" method="get">
<iLonWeb_url>
<iLonWeb func=TextField type=text symbol=NVL_nvo1 size="20"></iLonWeb>
<p>
<input type="submit" value="Update nvo1">
</form>
Standard HTML submit button. Every form must have some mechanism that indicates
the user has finished filling out the information in the textbox(s) and it is time to send
the information to the web server. The most common method for doing this is to use a
submit button. The Web browser recognizes that when a submit button click event
occurs, it is time to send the form to the web server (the i.LON 1000 in our case) to
process the form.
<form action="outputs.htm" method="get">
<iLonWeb_url>
<iLonWeb func=TextField type=text symbol=NVL_nvo1 size="20"></iLonWeb>
<p>
<input type="submit" value="Update nvo1">
</form>
The <
iLonWeb_url
> tag allows the i. LON 1000 to implement the necessary security to
prevent access to network variables on web pages that are outside of a user’s access
range. See Chapter 11 for more information on setting up i.LON 1000 web page
security)
When the i. LON 1000’s Web server serves
outputs.htm
the above HTML code is
translated to look like:
<form action="outputs.htm" method="get">
<INPUT TYPE=HIDDEN NAME=iLonWeb_URL VALUE=/forms/outputs.htm>
<INPUT TYPE=text NAME=NVL_nvo1 VALUE="0.0 0" MAXLENGTH=31 SIZE="20" >
<p>
<input type="submit" value="Update nvo1">
</form>
You can see the effect of the translation by viewing the source code in the browser.
Notice that <
iLonWeb_url
> has been translated to
<INPUT TYPE=HIDDEN
NAME=iLonWeb_URL VALUE=/forms/outputs.htm
>. The form-processing engine
decides which network variables to update based on the hidden field. The form-
processing engine will update all the network variables on the page listed in the
value
attribute of this hidden field. Because all NVs are sent to the engine when the form is
processed, it generally makes sense to have only one form per web page.