title: How to get the value of a textbox inside a <td> using the id of <tr> in jquery
body: <p>i have a table like this</p>
  
  <pre><code>&lt;table&gt;
  &lt;tr id ='1tr'&gt;
  &lt;td&gt;&lt;input type='textbox' value='1'&gt;&lt;/td&gt;
   &lt;td&gt;&lt;input type='textbox' value='2'&gt;&lt;/td&gt;
   &lt;/tr&gt; 
   &lt;tr id ='2tr'&gt;
    &lt;td&gt;&lt;input type='textbox' value='3'&gt;&lt;/td&gt;
    &lt;td&gt;&lt;input type='textbox' value='4'&gt;&lt;/td&gt;
    &lt;/tr&gt;
   &lt;/table&gt;
  </code></pre>
  
  <p>how i can get the value of text box in second td that is in tr with id 2tr</p>