在python django中使用HTML表单的简单计算器

Below is my html form:

以下是我的html表单：

<form id="calci_form" method="get" action="#">
 <input type="hidden" name="prev_val" value="{{prev_val}}"></input>
 <input type="hidden" name="curr_val" value="{{curr_val}}"></input>
 <input type="hidden" name="op_sign" value="{{opsign}}"></input>
 <div id="calculator">
 <table id="tableCalci">
 <tr  id="row1">
 <td colspan="4"><input type="text" value="0" class="display" name="user_input">{{result}}</input></td>
</tr>
 <tr>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
<tr class="hover">
<td><button id="7" name="numval" value="7" type="submit"></button></td>
<td><button id="8" name="numval" value="8" type="submit"></button></td>
<td><button id="9" name="numval" value="9" type="submit"></button></td>
<td><button id="plus" name="sym" type="submit" value="add">&plus;</button>      
</td>
</tr>
<tr>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
</tr>
 <tr class="hover">
<td><button id="4" name="numval" value="4" type="submit"></button></td>
<td><button id="5" name="numval" value="5" type="submit"></button></td>
<td><button id="6" name="numval" value="6" type="submit"></button></td>
<td><button id="minus" name="sym" value="minus" type="submit">&minus;   
</button></td>
</tr>
<tr>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
  <td>&nbsp;</td>
 <td>&nbsp;</td>
</tr>
 <tr class="hover">
 <td><button id="1" name="numval" value="1" type="submit"></button></td>
 <td><button id="2" name="numval" value="2" type="submit"></button></td>
 <td><button id="3" name="numval" value="3" type="submit"></button></td>
 <td><button id="times" name="sym" value="times" type="submit">&times;  
 </button></td>
 </tr>
 <tr>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr class="hover">
 <td>&nbsp;</td>
 <td><button id="0" name="numval" value="0" type="submit"></button></td>
 <td><button id="equal" name="sym" type="submit">&equals;</button></td>
 <td><button id="divide"; name="sym" type="submit" value="divide">&divide;   
 </button></td>
 </tr>
 </table>
 </div>
</form>
<form i