两个文本字段的总和 - javascript [英] Sum of two textfields - javascript

问题描述

我在网上找到了 [this][1]，相当困难的 javascript 示例，并且我已经在我的网站上成功实现了它.

但是，在这种情况下，我想获得一个新文本字段中两个小计的结果.

传统的 getElementbyId 和 total.value=total 不起作用.

编辑

 函数 doMath(){//捕获两个输入框的输入值var twogiga = document.getElementById('twogig').value;var Fourgiga = document.getElementById('fourgig').value;//将它们相加并显示var sum = parseInt(twogiga) + parseInt(fourgiga);document.getElementById('total').value = parseInt(sum);}

这是我使用的javascript.但出于某种原因，当我只有一个值 (twogig) 时，total 被设置为 NaN.我的脚本有什么问题?

解决方案

好吧，如果您已将 ID 分配给文本输入，例如:<input type="text" id="my_input"/>，那么您可以用 document.getElementById('my_input').value 调用它.

所以:

<前><input type="text" id="my_input1"/><input type="text" id="my_input2"/><input type="button" value="把它们加在一起" onclick="doMath();"/><script type="text/javascript">函数 doMath(){//捕获两个输入框的输入值var my_input1 = document.getElementById('my_input1').value;var my_input2 = document.getElementById('my_input2').value;//将它们相加并显示var sum = parseInt(my_input1) + parseInt(my_input2);document.write(sum);}

当然，这是一个非常基本的脚本，它不会检查以确保输入的值是数字.我们必须将字段转换为整数，否则它们将是字符串(因此 2+2 将等于 22).当按钮被点击时，该函数被调用，它为每个输入框创建一个变量，将它们转换为整数，将它们相加，然后输出我们的总和.

I found [this][1], rather difficult, javascript example online and I've implemented it with success in my website.

However, I would like to get the result of, in this case, the two subtotals in one new text-field.

The traditional getElementbyId and total.value=total didn't work out.

EDIT

 function doMath()
{
    // Capture the entered values of two input boxes
    var twogiga = document.getElementById('twogig').value;
    var fourgiga = document.getElementById('fourgig').value;

    // Add them together and display
    var sum = parseInt(twogiga) + parseInt(fourgiga);
    document.getElementById('total').value = parseInt(sum);
}

This is the javascript I use. But for some reason, when I have just one value (twogig), the total is set as NaN. What is wrong with my script?

解决方案

Well, if you have assigned ID's to text inputs, for example: <input type="text" id="my_input" />, then you can call it with document.getElementById('my_input').value.

So:

<input type="text" id="my_input1" />
<input type="text" id="my_input2" />
<input type="button" value="Add Them Together" onclick="doMath();" />

<script type="text/javascript">
    function doMath()
    {
        // Capture the entered values of two input boxes
        var my_input1 = document.getElementById('my_input1').value;
        var my_input2 = document.getElementById('my_input2').value;

        // Add them together and display
        var sum = parseInt(my_input1) + parseInt(my_input2);
        document.write(sum);
    }
</script>

Naturally, that is a very basic script, it doesn't check to make sure the entered values are numbers. We have to convert the fields into integers, otherwise they'll be strings (so 2+2 would equal 22). When the button is clicked, the function is called, which makes a variable for each input box, converts them to ints, adds them, and outputs our sum.

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