This has come up from time to time and the best way to do it is with a "customBehavior". There is a hidden docs page about customBehaviors - to read it go to "Tools > Other Tools", then scroll down to the other page to the bottom-most panel.
Notes:
-- Since the specific implementation here uses Splunk's core messaging, you need to have a Message module in the view. Here I've included it right above to the TextField but you can put it anywhere on the page.
<module name="Message" layoutPanel="panel_row1_col1">
<param name="filter">customValidator_1</param>
<param name="maxSize">1</param>
<param name="clearOnJobDispatch">True</param>
</module>
<module name="TextField" layoutPanel="panel_row1_col1">
<param name="name">ip_address</param>
<param name="label">IP</param>
<param name="customBehavior">customInputValidation</param>
and then to define the actual customBehavior, the following Javascript has to go in $SPLUNK_HOME/etc/apps/YOUR_APP/appserver/static/application.js
if (typeof(Sideview)!="undefined") {
Sideview.utils.declareCustomBehavior ("customInputValidation", function(textFieldModule) {
var messenger = Splunk.Messenger.System.getInstance();
textFieldModule.validate = function() {
var v = this.input.val();
return (/^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/.test(v));
};
textFieldModule.onValidationFail = function() {
messenger.send("info","customValidator_1", "You must enter a valid IP Address.");
};
textFieldModule.onValidationPass = function() {
messenger.clear();
};
});
}
This example was quickly derived from a slightly different working example that ships with Sideview Utils, in case you wanted to look at that one too. You can navigate to that view by going to /en-US/app/sideview_utils/testcases_for_textfield.xml
