ถ้าจะเก็บค่าจาก session ใน textfield มีวิธีทำอย่างไรคัย

<table width="426" border="0">
        <tr>
          <td width="69">เรื่อง</td>
          <td width="347"><span id="sprytextfield1">
            <label>
            <input name="in_topic" type="text" id="in_topic" size="50" />
            </label>
          <span class="textfieldRequiredMsg">A value is required.</span></span></td>
        </tr>
        <tr>
          <td>รายละเอียด</td>
          <td><span id="sprytextarea1">
            <label>
            <textarea name="in_detail" id="in_detail" cols="55" rows="5"></textarea>
            </label>
          <span class="textareaRequiredMsg">A value is required.</span></span></td>
        </tr>
        <tr>
          <td>โดย</td>
          <td><span id="sprytextfield2">
            <label>
            <input type="text" name="in_by" id="in_by" />
            </label>
          <span class="textfieldRequiredMsg">A value is required.</span></span></td>
        </tr>
        <tr>
          <td>Email</td>
          <td><label>
            <input type="text" name="textfield" id="textfield" />
          </label></td>
        </tr>
        <tr>
          <td>&nbsp;</td>
          <td><form id="form1" name="form1" method="post" action="show_detail.php">
            <label>
            <input type="submit" name="button2" id="button2" value="Add" />
            </label>
                    <label>
                    <input type="reset" name="button3" id="button3" value="Reset" />
                    </label>
          </form>          </td>
        </tr>