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Struts Questions and Answers
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47. Can I use JavaScript to submit a form?
You can submit a form with a link as below. BTW, the examples below assume you are in an block and 'myForm' is picked up from the struts-config.xml name field of the action.
<a href='javascript:void(document.forms["myForm"].submit()>My Link</a>
Now the trick in the action is to decode what action you intend to perform. Since you are using JavaScript, you could set a field value and look for it in the request or in the form.
... html/javascript part ...
<input type='hidden' value='myAction' />
<input type='button' value='Save Meeeee'
onclick='document.forms["myForm"].myAction.value="save";
document.forms["myForm"].submit();' />
<input type='button' value='Delete Meeeee'
onclick='document.forms["myForm"].myAction.value="delete";
document.forms["myForm"].submit();' />
... the java part ...
class MyAction extends ActionForm implements Serializable {
public ActionForward execute (ActionMapping map, ActionForm form,
HttpServletRequest req, HttpServletResponse) {
String myAction = req.getParameter("myAction");
if (myAction.equals("save") {
// ... save action ...
} else if (myAction.equals("delete") {
// ... delete action ...
}
}
}
}
This is just one of many ways to achieve submitting a form and decoding the intended action. Once you get used to the framework you will find other ways that make more sense for your coding style and requirements. Just remember this example is completely non-functional without JavaScript.
Here is a link which utilizes the LookupDispatch action to submit forms with multiple actions without javascript: http://husted.com/struts/tips/003.html
48. How do I use JavaScript to ...
Struts is mainly a server-side technology. We bundled in some JSP tags to expose the framework components to your presentation page, but past that, the usual development process applies.
Interactive pages require the use of JavaScript. (That's why it was invented.) If you want things popping up or doing this when they click that, you are outside the scope of Struts and back into the web development mainstream.
You use JavaScript with Struts the same way you use with any presentation page. Since JavaScript is a client-side technology, you can use simple relative references to your scripts. If you need to fire a JavaScript from a HTML control, the Struts HTML tags have properties for the JavaScript events.
A very good JavaScript resource is Matt Kruse's site at http://www.mattkruse.com/javascript/
Do I need to implement reset and set all my form properties to their initial values?
No. You need to set checkbox properties to false if the ActionForm is being retained in session scope. This is because an unchecked box does not submit an attribute. Only checked boxes submit attributes. If the form is in session scope, and the checkbox was checked, there is no way to turn it back off without the reset method. Resetting the properties for other controls, or for a request scope form, is pointless. If the form is in request scope, everything already just started at the initial value.
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