title: how to get value from table td using javascript
body: <p>i want to get the value of <strong>Save</strong> using jquery through input on keyup function.. i am matching value with <strong>Buy</strong>..means if value matched with the value(range) of <strong>Buy</strong>..then get the value of <strong>Save</strong>..
  for example if i entered 3 in textfield then it gets value from <strong>Save</strong> 45%..and if i entered 8 then result should be 51%..entered 15 result 56% and so on. 
  here is image link for better understanding.</p>
  
  <p><a href="http://easycaptures.com/fs/uploaded/807/3129634990.jpg" rel="nofollow">http://easycaptures.com/fs/uploaded/807/3129634990.jpg</a></p>
  
  <pre><code>&lt;table class="attribute_table"&gt;
      &lt;tbody&gt;
        &lt;tr&gt;
          &lt;th&gt;Buy&lt;/th&gt;
          &lt;th&gt;Unit&lt;/th&gt;
          &lt;th&gt;Price/unit&lt;/th&gt;
          &lt;th class="save_red"&gt;Save&lt;/th&gt;
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;3-5&lt;/td&gt;
          &lt;td&gt;Pairs&lt;/td&gt;
          &lt;td class="td_price"&gt;&lt;span class="price"&gt;$4.99&lt;/span&gt;&lt;/td&gt;
          &lt;td class="save_red"&gt;45%&lt;/td&gt;
  
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;6-11&lt;/td&gt;
          &lt;td&gt;Pairs&lt;/td&gt;
          &lt;td class="td_price"&gt;&lt;span class="price"&gt;$4.49&lt;/span&gt;&lt;/td&gt;
          &lt;td class="save_red"&gt;51%&lt;/td&gt;
  
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;12-23&lt;/td&gt;
          &lt;td&gt;Pairs&lt;/td&gt;
          &lt;td class="td_price"&gt;&lt;span class="price"&gt;$3.99&lt;/span&gt;&lt;/td&gt;
          &lt;td class="save_red"&gt;56%&lt;/td&gt;
  
        &lt;/tr&gt;
        &lt;tr&gt;
          &lt;td&gt;24+&lt;/td&gt;
          &lt;td&gt;Pairs&lt;/td&gt;
          &lt;td class="td_price"&gt;&lt;span class="price"&gt;$3.90&lt;/span&gt;&lt;/td&gt;
          &lt;td class="save_red"&gt;57%&lt;/td&gt;
  
        &lt;/tr&gt;
      &lt;/tbody&gt;
    &lt;/table&gt;
  </code></pre>
  
  <p>here is input field</p>
  
  <pre><code>&lt;label for=""&gt;Enter Quantity&lt;/label&gt;
    &lt;input type="text" name="qty" id="qty"&gt;&lt;/input&gt;
  </code></pre>
  
  <p>i have tried some code but still no luck..</p>