maxlength for text box
<pre data-sub="prettyprint:_">
<textarea rows="10" cols="25" maxlength="25" onkeypress="return TextUtil.isNotMax(this)"></textarea>
TextUtil.isNotMax = function(oTextArea) {return oTextArea.value.length != oTextArea.getAttribute(“maxlength”);}
var TextUtil = new Object();
</pre>