Increase/decrease value of input integer fieldset with buttons/inputs using Jquery/js
<p>I need to have a series of inputs, with a preset value, each a different integer, and have 1 button that when pressed increases(and another button that decreases) these input values by a preset amount. Say I have inputs of values 10, 20, 30, and then I can increase these values by pressing on a button, say of value 10, so that these input values are updated simultaneously to being 20, 30, 40. I researched about 5-6 previous answers that describe something very similar, but too often "Id" is used whereas I need to reference a class of inputs. One of the codes found here that semi-works is in the following, culled from an answer several years back. 
HTML:</p>

<pre><code>&lt;input name="qty" id="qty" type="text" value="10" size="3" &gt;
 &lt;input name="qty" id="qty1" type="text" value="20" size="3" &gt;
 &lt;input type="button" id="qtyplus" value="+" onclick="return false"&gt;
 &lt;input type="button" id="qtyminus" value="HELLO" onclick="return  false"&gt;
</code></pre>

<p>Jquery:</p>

<pre><code> &lt;script type="text/javascript" src="js/jquery.min.js"&gt;&lt;/script&gt;
 &lt;script&gt;jQuery(function(){
 jQuery("#qtyplus").click(function(){     
 jQuery(":text[name='qty']").val(     Number(jQuery(":text[name='qty']").val()) + 1 );
 });
 jQuery("#qtyminus").click(function(){
  if(jQuery('#qty').val()&gt;1)
  jQuery(":text[name='qty']").val(    Number(jQuery(":text[name='qty']").val()) - 1 );

});
});
</code></pre>

<p>There's also a previously authored <a href="http://jsfiddle.net/hMS6Y/" rel="nofollow">jfiddle</a> from another posting that I can't make to work for my purposes.</p>