Submit button and function coding

Submit button and function coding

I am new to Javascript and jQuery. I have a form with a multiple submit buttons, each with an id. In the example below, the id="modify". What I want to do, is create a click event (or submit event) that will execute the code within the called function 'modify''.

I have the function code in the head section and the form's submit button in the body. Here is the code I have been trying to get to work:

<script type="text/javascript" src="../schedule/js/jquery-1.7.1.min.js"></script>

<script>
document.onload initAll():

function initAll(){
    document.mainContainer.getElementById("modify").submit = showResults;
}

function showResults(){
    alert("It worked!");
}
</script>

<body>
<fieldset form id="maintContainer" style="border:none; display:none;">
       
    <form name="modifyJob" id="modifyJob" action="modify" >
        <fieldset>
            <legend><strong>&nbsp;&nbsp;MODIFYNAMD&nbsp;&nbsp;</strong></legend>
           
            Job ID#:    <select name="IdNum" style="margin-left: 15px;">
                        <option value="#">Choose....</option>
                    </select><br>
                    <input type="submit" value="Do It!" onclick=initAll()>
                   
        </fieldset>
    </form>
</body>