Getting NaN from form PHP form using JS - php

Question

I'm getting a NaN value if i try to do any math with the two vars i pull form the form. It also gives me NaN if i try it parseInt it. IDK if it helps but the values are pulled from the URL using PHP; example: .../serch.php?animal=all&color=any&sunSd=all&lifeSpn=all&limiterF=5&limiterT=20
limiterF and limiterT are the vars I'm working with.
html:
<form id='serchForm' action="serch.php" method="GET">
...
<fieldset>
From: <input type='text' id = 'limiterFid' name='limiterF' value=<?php if (!empty($_GET['limiterF'])) {echo $limiterF;} else {echo 0;} ?> size="2" /><br />
To: <input type='text' id = 'limiterTid' name='limiterT' value=<?php if (!empty($_GET['limiterT'])) {echo $limiterT;} else {echo 20;} ?> size="2" />
</fieldset>
<input type="submit" id="submitNew" />
<input type="submit" id="nextSerch" />
JS:
$(document).ready(function() {
$("#serchForm input").click(function(e) {
if(e.target.id == 'submitNew') {
e.preventDefault();
$('#limiterFid').attr("value", 0);
$('#limiterTid').attr("value", 20);
$("#serchForm").submit();
} else if (e.target.id == 'nextSerch') {
e.preventDefault();
var limiterF = $('#limiterFid').value,
limiterT = $('#limiterTid').value;
limiterT = limiterF + limiterT;
limiterF = parseInt(limiterF, 5);
$('#limiterFid').attr("value", limiterF);
$('#limiterTid').attr("value", limiterT);
$("#serchForm").submit();
} else {
return;
}
});
});
This is what it will return when you click nextSerch:
.../serch.php?animal=all&color=any&sunSd=all&lifeSpn=all&limiterF=NaN&limiterT=NaN

Answer 1

value is a property of the DOM element not the jQuery object. You can use either val() or value on the original DOM element.
$('element').val()
// OR
$('element')[0].value
Also to set values you typically don't use attr, you use val.
$('element').val('newValue')

Answer 2

Use the .val() method, as value will returned undefined as it is attempting to call the 'value' property of a jQuery object:
$(document).ready(function() {
$("#serchForm input").click(function(e) {
if(e.target.id == 'submitNew') {
e.preventDefault();
$('#limiterFid').val(0);
$('#limiterTid').val(20);
$("#serchForm").submit();
} else if (e.target.id == 'nextSerch') {
e.preventDefault();
var limiterF = $('#limiterFid').val(),
limiterT = $('#limiterTid').val();
limiterT = limiterF + limiterT;
limiterF = parseInt(limiterF, 5);
$('#limiterFid').val(limiterF);
$('#limiterTid').val(limiterT);
$("#serchForm").submit();
} else {
return;
}
});
});