实现加减法

Question

大家好，我是新手，我遇到一个问题，希望高手们能帮我解决一下。谢谢
现在我正在做一个小的应用程序，
例子：
工作时间输入界面，初始默认非项目工时100小时，事假0小时，当填写项目工时时，非项目工时自动相应减少保证总工时和为100小时；在该界面增加工时填写说明。怎么样才能实现这个加减法呢？？？如果好的答应发

Answer 1

用js。
<asp:TextBox ID="txt1" runat="server" onkeyup="KeyPress(this,txt2)"></asp:TextBox>
<asp:TextBox ID="txt2" runat="server"></asp:TextBox>function KeyPress(obj1,obj2) 
{ 
    obj2.value = 100 - obj1.value;
}

Answer 2

服了你，你参考下。写自己的
function KeyPress(obj1,obj2)  
{  
  obj2.value = 100 - obj1.value;
}function KeyPress(obj1,obj2,obj3) 
{
    //里面你想怎么计算就怎么计算。
}

Answer 3

能不能给做一个具体的方案出来
例如：<td align="left" style="width: 20%;">
                                项目名称
                            </td>
                            <td align="left" style="width: 20%;">
                                工时数【100小时】
                            </td>
                            <td align="left" style="width: 20%;">
                                操作
                            </td>
                        </tr>
                        <tr align="left" style="border-style: None; font-size: Small;">
                            <td style="display: none; width: 0%;">
                                <label id="projectcode">
                                    FXMGS
                                </label>
                            </td>
                            <td>
                                非项目工时
                            </td>
                            <td>
                                <input id="txthours" type="text" />
                            </td>
                            <td>
                            </td>
                        </tr>
                        <tr align="left" style="border-style: None; font-size: Small;">
                            <td style="display: none; width: 0%;">
                                <label id="projectcode">
                                    SJ
                                </label>
                            </td>
                            <td>
                                事假
                            </td>
                            <td>
                                <input id="txthours" type="text" />
                            </td>
                            <td>
                            </td>
                        </tr>
                        <tr id="model" align="left" style="border-style: None; font-size: Small;">
                            <td style="display: none; width: 0%;">
                                <label id="projectcode">
                                </label>
                            </td>
                            <td>
                                <select id="select_project">
                                </select>
                            </td>
                            <td>
                                <input id="txthours" type="text" />
                            </td>
<td>
                                项目工时
                            </td>
                            <td>
                                <input id="txthours" type="text" />
                            </td>怎么实现我输入项目工时和事假，在非项目工时文本框里显示剩余的时间急需，谢谢！！

Answer 4

<asp:TextBox ID="txt1" runat="server" ></asp:TextBox>
<asp:TextBox ID="txt2" runat="server"></asp:TextBox>
<asp:TextBox ID="txt3" runat="server" onkeyup="cal()" ></asp:TextBox>
function cal()  
{  
   var a= parseFloat(document.getElementById("txt1").value);
   var b= parseFloat(document.getElementById("txt2").value);
   document.getElementById("txt2").value= 100-a-b;
}