How do i make my HTML page to remain after clicking submit?

I want after the user enter submit that the开发者_JAVA百科 page will not change.

        <script src="doAction.js" language="Javascript" type="text/javascript"></script>
    <form name = "ex4Param" id="ex4Param"  method="post" onsubmit="doAction();" >
        <fieldset>
            <legend>Input section</legend>
        Query Sequence:<br/>
        <td><textarea rows="5" cols="84" id="enhancers" name="charSequence"></textarea></td>
             <form/>

---

onsubmit="return doAction();"

In doAction: return false