19. XHTML MP Selection Lists

A selection list is a list of options that a user can select. The <select></select> tags define a selection list in XHTML MP. One or more <option></option> tag pairs are enclosed within the <select></select> tags. The <option></option> tag pair defines a list item.

To send the value of the selected item to the server, the <select> tag has to be used in conjunction with the <form> tag. You can learn how to use the <form> tag and how to read the value of the selected item at the server later in the "Sending Data to the Server in XHTML MP" section of this tutorial.

The name attribute of the <select> tag specifies the name of a selection list. At the server-side, the name will be used to retrieve the value of the selected item. The value of an item is specified with the value attribute of the <option> tag.

Let's take a look at the following XHTML MP example. It can help you understand better what we are talking about.

(selListEg1.xhtml)

The result of the above XHTML MP example in WAP browsers is shown below.

Sony Ericsson T610	Nokia Mobile Browser 4.0

If you select the selection list, the options available will be displayed like this:

Sony Ericsson T610	Nokia Mobile Browser 4.0

The selected attribute of the <option> tag can be used to set the default option. The default option will be initially selected. The selected attribute only accepts the value "selected". Here is an example that shows how to pre-select the second option "XHTML MP Tutorial Part B":

<option value="tutorial_B" selected="selected">XHTML MP Tutorial Part B</option>

19.1. Selecting Multiple Options

In the previous XHTML MP example, a user can only select one option of the selection list. To allow a user to select multiple options, you need to make use of the multiple attribute of the <select> tag. The multiple attribute can only be assigned with the value "multiple". Options in such kind of selection lists are displayed as check boxes on the screen.

Let's take a look at the following XHTML MP example:

(selListEg2.xhtml)

The result of the above XHTML MP code is shown below:

Sony Ericsson T610

Nokia Mobile Browser 4.0

When the multiple attribute is present in the <select> tag, it is possible to specify multiple default options. To do so, add selected="selected" to each of the <option> tags that should be selected by default. Here is an example:

<select name="selectionList" multiple="multiple">
  <option value="tutorial_A" selected="selected">XHTML MP Tutorial Part A</option>
  <option value="tutorial_B" selected="selected">XHTML MP Tutorial Part B</option>
  <option value="tutorial_C">XHTML MP Tutorial Part C</option>
</select>

The above lines of code tell the WAP browser that the first and second options of the selection list should be pre-selected.

19.2. Organizing Options in XHTML MP Selection Lists

If an XHTML MP selection list contains too many options, it will look disorganized. To tackle this, you can arrange options into groups. You define an option group using the <optgroup></optgroup> tag pair. The label attribute of the <optgroup> tag specifies the title of an option group.

The usage of the <optgroup></optgroup> tags is shown in this XHTML MP example:

(selListEg3.xhtml)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.0//EN" "http://www.wapforum.org/DTD/xhtml-mobile10.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <title>XHTML MP Tutorial</title>
  </head>

  <body>
    <form method="get" action="xhtml_mp_tutorial_proc.asp">
      <p>
        <select name="selectionList">
          <optgroup label="Tutorial Ch1">
            <option value="tutorial_1A">Part 1A</option>
            <option value="tutorial_1B">Part 1B</option>
            <option value="tutorial_1C">Part 1C</option>
          </optgroup>
          <optgroup label="Tutorial Ch2">
            <option value="tutorial_2A">Part 2A</option>
            <option value="tutorial_2B">Part 2B</option>
            <option value="tutorial_2C">Part 2C</option>
          </optgroup>
          <optgroup label="Tutorial Ch3">
            <option value="tutorial_3A">Part 3A</option>
            <option value="tutorial_3B">Part 3B</option>
            <option value="tutorial_3C">Part 3C</option>
          </optgroup>
        </select>
      </p>
    </form>
  </body>
</html>

This is the result of the above XHTML MP example in WAP browsers:

Sony Ericsson T610

Nokia Mobile Browser 4.0

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