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List Boxes and Combo Boxes

if (iMin == null || iValue > parseInt(iMin)) {

oTextbox.value = (iValue - 1);

}

};

The few lines added to the method do some very specific things. First, the minimum and maximum val-

ues are retrieved from the custom attributes. Then, when each key is tested, a test checks whether the min-

imum and maximum values have been specified. If the attributes haven’t been specified,

iMax

and

iMin

are equal to

null

. If they aren’t

null

parseInt()

is called to get the integer value of the attributes. This

value is then compared with the value in the text box to determine it is should be changed (incremented

or decremented) or not.

To use this functionality, just add either the

min

attribute or the

max

attribute (or both) to the

tag:

<input type=”text” onkeypress=”return TextUtil.allowChars(this, event)”

validchars=”0123456789” onblur=”TextUtil.blurAllow(this)”

onkeydown=”TextUtil.numericScroll(this, event)”

max=”100” min=”0” />

Using this code, the values will stop incrementing and decrementing when either of these limits is hit.

List Boxes and Combo Boxes

List boxes and combo boxes are created using the HTML

element. By default, the browser

renders the

element as a combo box:

</select>

The

value

attribute of each

is used to determine the value for the control as a whole; the

selected option gives its

value

to the control (so it can be sent to the server).

To render this same code as a list box, you need only add the

size

attribute and indicate how many

items you want visible at the same time. For example, the following displays a list box with three items

visible at once.

</select>

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