1、代码
1 <script>
2 function sum(){ //加法
3 var value1 = document.getElementById("num1").value;
4 var value2= document.getElementById("num2").value;
5 var result = parseInt(value1)+parseInt(value2);//转换为数字,再进行加法
6 document.getElementById("result1").value=result; // 把result作为result1这个方框ID的输出
7 }
8 </script>
9
10 <script>
11 function sub(){ //加法
12 var value3 = document.getElementById("num3").value;
13 var value4= document.getElementById("num4").value;
14 var result = parseInt(value3)-parseInt(value4); //转换为数字,再进行减法
15 document.getElementById("result2").value=result; //把result作为result2这个方框ID的输出
16 }
17 </script>
18
19 <table >
20 <tr>
21 <td width="100px" ><input type="number" id="num1" value="1" color="red"> </td>
22 <td width="40px">+</td>
23 <td width="100px" ><input type="number" id="num2" value="2"> </td>
24 <td width="70px">=</td>
25 <td width="100px" > <input type="number" id="result1" value=""></td>
26 <td width="70px"><input type="button" value="加法" onclick="sum()" ></td>
27 </tr>
28
29 <tr>
30 <td width="100px" ><input type="number" id="num3" value="1"> </td>
31 <td width="40px">-</td>
32 <td width="100px" ><input type="number" id="num4" value="2"> </td>
33 <td width="70px">=</td>
34 <td width="100px" > <input type="number" id="result2" value=""></td>
35 <td width="70px"><input type="button" value="减法" onclick="sub()" ></td>
36 </tr>
37 </table>
2、效果