[Wonder-disc] IE javascript error in wonder.js

[Simon <si...@po...>]

hi all -

AjaxModalDialog, contains update containers, observefields etc. User
clicks an AjaxUpdateLink which toggles the section of the component in
view from one form to another (forms are wrapped in an update
container, observe field is wrapped around the contents of each form).

Across all IE browsers (5,6,7,8,9) we are seeing this exception:

'null' is null or not an object (wonder.js line 379)

line 379 is this: var actionUrl = form.action;

highlighted below in the code below.

anyone got any ideas what's going on ??

Thanks, Simon

ps. wonder revision 11611


var AjaxSubmitButton = {
	PartialFormSenderIDKey: '_partialSenderID',
	
	AjaxSubmitButtonNameKey: 'AJAX_SUBMIT_BUTTON_NAME',
	
	defaultOptions: function(additionalOptions) {
		var options = AjaxOptions.defaultOptions(additionalOptions);
		options['method'] = 'post';
		return options;
	},
	
	generateActionUrl: function(id, form, queryParams, options) {
		var actionUrl = form.action; <<<< LINE 379
		if (queryParams != null) {
			actionUrl = actionUrl.addQueryParameters(queryParams);
		}
		actionUrl = actionUrl.sub('/wo/', '/ajax/', 1);
		if (id != null) {
			if (options && options['_r']) {
				actionUrl = actionUrl.addQueryParameters('_r=' + id);
			}
			else {
				actionUrl = actionUrl.addQueryParameters('_u=' + id);
			}
		}
		actionUrl = actionUrl.addQueryParameters(new Date().getTime());
		return actionUrl;
	},