Jquery if statement based on input values

I'm making a simple form and I'm having trouble getting it to do what I want. On form submission I need it to detect if multiple inputs of a certain category have values greater than 0 (because only one should be selected). Here's the html of the form

      <form onsubmit="calcTime();">

  <table>
    <tr>
      <p>How long does the task take to perform?  (Choose one)</p></tr>
    <tr>
      <p>
        <input type="text" style="width: 3em;" id="seconds">&nbsp;  Seconds (Enter an integer 1-60)
        <input type="text" style="width: 3em;" id="minutes">&nbsp;  Minutes (Enter an integer 1-60)
      </p>
    </tr>
    <br>
    <tr>
      <p>How often do you perform the task? (Choose one)</p></tr>
    <tr>
      <p><input type="text" style="width: 3em;" id="day">&nbsp;x Per day&nbsp;
        <input type="text" style="width: 3em;" id="week">&nbsp;x Per week&nbsp;
        <input type="text" style="width: 3em;" id="month">&nbsp;x Per month&nbsp;
        <input type="text" style="width: 3em;" id="year">&nbsp;x Per year&nbsp;
      </p>
    </tr>
    <br>
    <tr>
      <p><input type="submit" value="Submit" id="submitButton"></p>
    </tr>

    <br>
    <tr>
      <p id="result"></p>
    </tr>
  </table>
</form>

The jQuery function that isn't working so far is this...

function calcTime() {
var seconds = $('#seconds');
var minutes = $('#minutes');
var perDay = $('#day');
var perWeek = $('#week');
var perMonth = $('#month');
var perYear = $('#year');
if ((seconds.value > 0) && (minutes.value > 0)) {
alert('Please only choose either seconds or minutes!');
return false;
  }
}

Thanks