Is there a way to change the button color when an input field is in focus? I'm open to using either JavaScript or CSS for this. Thanks in advance for any assistance.
.redbutton {
background-color:red;
}
<form accept-charset="UTF-8" method="post" action="http://go.pardot.com/l/213532/2016-08-08/jr9" class="form" id="pardot-form">
<p class="form-field first_name pd-text required required-custom">
<label class="field-label" for="213532_2892pi_213532_2892">First Name *</label>
<input type="text" name="213532_2892pi_213532_2892" id="213532_2892pi_213532_2892" value="" class="text" size="30" maxlength="40" onchange="" />
</p>
<p class="form-field last_name pd-text required required-custom">
<label class="field-label" for="213532_2894pi_213532_2894">Last Name *</label>
<input type="text" name="213532_2894pi_213532_2894" id="213532_2894pi_213532_2894" value="" class="text" size="30" maxlength="80" onchange="" />
</p>
<p class="form-field email pd-text required required-custom">
<label class="field-label" for="213532_2896pi_213532_2896">Email *</label>
<input type="text" name="213532_2896pi_213532_2896" id="213532_2896pi_213532_2896" value="" class="text" size="30" maxlength="255" onchange="piAjax.auditEmailField(this, 213532, 2896, 14168);" />
</p>
<p class="submit">
<input type="submit" accesskey="s" value="SUBMIT" />
</p>
</form>