想要在javascript中添加两个文本框值，以便当我离开第二个文本框时，第三个将给出前两个的附加值 [英] Want to add two textbox value in javascript, So that when I leave 2nd textbox , 3rd will give added value of first two

问题描述

这是我的javascript代码:-

This is my javascript code:-

<script language="javascript" type="text/javascript">

            function functn() {
                var a = document.getElementById('TextBox1').value;
                var b = document.getElementById('TextBox2').value;
                if (a == "")
                    a = 0;
               else if (b == "")
                    b = 0;

                var res = parseInt(a) + parseInt(b);
                if (!NaN(res)) {
                    document.getElementById('TextBox3').value = res;
                }

                else
                    document.getElementById('TextBox3').value = 0;
            }

        </script>

        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
        <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
        <asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>

无法弄清楚我错了.需要帮助！

Can''t figure out where I''m wrong. Need HELP!!

推荐答案

您的编码中有几件不好的事情.

There is several bad thing in your coding.

function functn() {
    //no problem
    var a = document.getElementById('TextBox1').value;
    //no problem
    var b = document.getElementById('TextBox2').value;
    if (a == "")
        a = 0;
//problem
//why:
//if a=="" then next statement do not get verified
//what to do? : remove else
   else if (b == "")
        b = 0;
//no problem
    var res = parseInt(a) + parseInt(b);
    //problem;
    //big problem; 
    //if you check on debugger ">typeof NaN", you will get "number"; NaN is not a function. you are suppose to check isNaN; your problem will be solved, I guess.
    if (!NaN(res)) {
        document.getElementById('TextBox3').value = res;
    }
    else
        document.getElementById('TextBox3').value = 0;
//other than the one compilation error and one logical error everything seems fine. 
}

如何调试:我使用三种软件来调试与网络相关的问题
1. Firefox:(ctrl + shift + k)
2. Chrome:(ctrl + shift + j)
3. Internet Explorer(11)；偶尔(F12)

因此，打开，例如说Chrome，按ctrl + shift + j
然后在新打开的控制台中编写functn()
按Enter
您会看到函数错误；

无论如何，给它一个机会.

How to debug: I use three software to debug web related issues
1. Firefox : (ctrl+shift+k)
2. Chrome : (ctrl+shift+j)
3. Internet Explorer(11); occasionally(F12)

so, open, say Chrome, press ctrl+shift+j
and then write, in the newly opened console, functn()
press enter
you will see your function error;

anyway, give it a shot.

所以我找到了一个按钮单击事件的解决方案:-

So I found a solution with the button click event:-

<script language="javascript" type="text/javascript">

            function functn() {
                var a = document.getElementById('TextBox1').value;
                var b = document.getElementById('TextBox2').value;
                if (a == "")
                    a = 0;
                if (b == "")
                    b = 0;

                var res = parseInt(a) + parseInt(b);
                //if (!NaN(res))
                {
                    document.getElementById('TextBox3').value = res;
                }


            }

        </script>

        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
        <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
        <button id="Button7" value="Click" onclick="functn()">Click</button>
        <asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>

但是我不需要按钮.

我想要的是，一旦离开第二个文本框，第三个文本框就会自动获得总和.

But I want no buttons.

What I want is, as soon as I leave the 2nd textbox, the 3rd textbox gets the sum automatically.

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