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Handling HTML messages
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When errors are found in the user's input, it is necessary to send one or more messages to the browser. Formatting and outputting such messages can be tedious, repetitive, and error-prone.

You can more easyly perform this task, using Mel's service program HTML message support. Do the following:

  1. In the external HTML source member create a set of sections to be used for message outputting. The standard set is available in CGIDEV2/HTMLSRC member TALK2. The standard set must
    1. contain section names MsgStart, MsgL1, MsgL2, MsgL3, MsgEnd
    2. a /%msgtext%/ variable must exist in sections MsgL1, MsgL2, MsgL3
    Look at the example from TALK2: 
    /$top
Content-type: text/html

<HTML>
  <HEAD>
    <TITLE>Response To Talk To Us</TITLE>
    <style TYPE="text/css">
         <!--
           .centeredtitle { color: Blue; font-weight: Bold; font-size: 24pt; text-align: center }
           .emphasize {color: Blue; font-weight: Bold; }
           .indent40 {margin-left: 40px; }
           .messagestart, .message1, .message2, .message3  {color: Red; font-weight: Bold; }
             .messagestart { font-size: 16pt }
             .message1 { margin-left: 20px; text-indent: -12px; font-size: 12pt }
             .message2 { margin-left: 40px; text-indent: -10px; font-size: 10pt }
             .message3 { margin-left: 60px; text-indent: -10px; font-size: 10pt }
         -->
    </style>
  </HEAD>
<BODY>
      <!--  ... etc. ... -->
/$MsgStart
<div class=messagestart>Errors:</div>

/$MsgL1
<div class=message1>- /%msgtext%/</div>

/$MsgL2
<div class=message2>- /%msgtext%/</div>

/$MsgL3
<div class=message3>- /%msgtext%/</div>

/$MsgEnd
<div class=messagestart><hr></div>

  2. Optionally you may use subprocedure CfgMsgs to override the default externally described HTML names:
    • message text field name (msgtxt),
    • starting section name (msgstart),
    • level 1 section name (msgl1),
    • level 2 section name (msgl2),
    • level 3 section name (msgl3),
    • ending section name (msgend).
  3. Use subprocedure ClrMsgs to clear the messages stored in the service program's arrays and to set their count to zero
  4. Use subprocedure AddMsg to add a message's text and formatting level (1, 2, or 3) to the service program's arrays
  5. Use subprocedure GetMsgCnt to retrieve the number of messages currently stored in the service program's arrays. It can be used to condition calling WrtMsgs.
  6. Use subprocedure WrtMsgs to write the messages in the arrays to standard output. If no messages are there, nothing is done.

For examples of using HTML messages, please look at the source of RPG CGI program TEMPLATE.