JavaScript html表单计算器不起作用

Question

im trying to make a simple perimeter calculator for a projector screen. 我试图为投影仪屏幕制作一个简单的周长计算器。

The code should take the response from a radio button input and the diagonal length to calculate the perimeter accordingly. 代码应从单选按钮输入和对角线长度中获取响应，以相应地计算周长。

here is my code atm: 这是我的代码atm：

<html>

    <body>
        <script language="javascript">
            function calc() {
                var form = document.forms.Calculator;
                var A = Number(getSelectedValue(form.elements.A));
                var B = Number(getSelectedValue(form.elements.B));


                if (A = 0) {
                    L = 0.8;
                    H = 0.6;
                } else if (A = 1) {
                    L = 0.872;
                    H = 0.49;
                } else {
                    L = 0.922;
                    H = 0.386;
                }

                form.elements.Total.value = 2 * B * (L + H);

            }

            function getSelectedValue(flds) {
                var i = 0;
                var len = flds.length;

                while (i < len) {
                    if (flds[i].checked) {
                        return flds[i].value;
                    }
                    i++;
                }

                return "";
            }
        </script>
        <title>Calculator</title>   <pre>
    <form name="Calculator">
        <label>A</label> 
            4:3: <input name="A" type="radio" onChange="calc()" value="0" checked>
            16:9: <input name="A" type="radio" onChange="calc()" value="1">
            2.39:1: <input name="A" type="radio" onChange="calc()" value="2">
        <label>B</label>
            Screen Size: <input name="B" type="text" onChange="calc()" checked>
        <label>Total</label> 
            <input type="text" name="Total" onChange="calc()" readonly size="10"><br> 
        <input type="submit" value="Submit Calculation"> <input type="reset" value="Clear"> 
    </form>
    </pre>

    </body>

</html>

Answer 1

Your function getSelectedValue is wrong. 您的函数getSelectedValue错误。 It loops trough an array of elements to see which one is checked. 它循环遍历一组元素以查看已检查的元素。 You are trying to do the same for B which is only one element so that is not going trough the loop and thus returns '' . 您正在尝试对B进行相同操作， B仅是一个元素，因此不会经过循环并因此返回'' 。

So instead of 所以代替

var B = Number(getSelectedValue(form.elements.B));

try 尝试

var B = Number(form.elements.B.value);

Also, your if else statements are wrong. 另外，您的if else陈述是错误的。 It should be == instead of = : 应该是==而不是= ：

if (A == 0) {
    L = 0.8;
    H = 0.6;
} else if (A == 1) {
    L = 0.872;
    H = 0.49;
} else {
    L = 0.922;
    H = 0.386;
}

JavaScript html表单计算器不起作用

问题描述

1 个解决方案

解决方案1
0 2013-08-23 18:04:07

JavaScript html表单计算器不起作用

问题描述

1 个解决方案

解决方案1 0 2013-08-23 18:04:07

解决方案1
0 2013-08-23 18:04:07