Change drupal font color based on variables
Yes, you can achieve this with jQuery.

In a custom module add the following code.

function custommodule_form_alter(&amp;$form,$form_state,$form_id) {
  if ($form_id == "yourcontent type form") {
    $form['field_field1']['#attributes'] = array('id' =&gt; 'field1_id');
    drupal_add_js(drupal_get_path('module', 'custommodule') . '/jsfilename.js', ));    
  }
}


Put this in jsfilename.js.

(function($) {
  Drupal.behaviors.custommodule = {
    attach: function (context, settings) {
      // I suppose your field1 html elemet ID=field1_id
      $('#field1_id').change(function() {
        if($('#field1_id').val() &lt; 50) {
          $(this).css("color","yellow"); // you can add class to it and in css file style it  ex:$(this).addClass('class1');
        }
        else if($('#field1_id').val() &gt; 50 &amp;&amp; $('#field1_id').val() &lt; 70) {
          $(this).css("color","red");
          $(this).css("color","yellow"); // you can add class to it and in css file style it  ex:$(this).addClass('class1');
        }
        // …  
      });
    }
  }
}