1

这包括两个问题。第一个问题是将数字四舍五入到某个小数点。第二个问题是将下拉菜单连接到右小数点。

首先我的代码:

<style>
  span{font-style:italic;}
  span{color:green;}
</style>

<script>
    function calcul(){
            var sales = parseFloat(document.getElementById("sales").value);
            var OpExp = parseFloat(document.getElementById("OpExp").value);
            var TaxAll = parseFloat(document.getElementById("TaxAll").value);
            var Depre = parseFloat(document.getElementById("Depre").value);
            var Divid = parseFloat(document.getElementById("Divid").value);
            var TaxR = parseFloat(document.getElementById("TaxR").value);
            //GP = Gross Profit
            var GP = sales - OpExp;
            //TaxInc = Taxable Income
            var TaxInc = GP + TaxAll;
            //NetInc = Net Income
            var NetInc = TaxInc - ((TaxR / 100) * TaxInc);
            document.getElementById("NetIncome").innerHTML= 
            TaxInc - ((TaxR / 100) * TaxInc);
            //AtRE = Addition to Retained Earnings
            document.getElementById("AtRE").innerHTML = NetInc - Divid;
        }
</script>

<form action="" id="nothing">
In 2007 the British building firm Balfour Betty plc had sales of 
<input type="text" id="sales" maxlength="6" size="6"> 
million, total operating expenses of 
<input type="text" id="OpExp" maxlength="6" size="6"> 
million, a tax allowance (rebate) of 
<input type="text" id="TaxAll" maxlength="6" size="6"> 
million because of past losses, and 
<input type="text" id="Depre" maxlength="6" size="6"> 
depreciation. <strong>What is the net income of the
firm?</strong><br />
<br />
Balfour Betty plc paid out <input type="text" id="Divid" maxlength="6" size="6"> million 
in cash dividends. <strong>What is the addition to retained earnings?</strong><br />
<br />
The tax rate is <input type="text" id="TaxR"  maxlength="6" size="6"> %.<br />
<br />
  <input type="button" value="Calculate" id="but" onclick="calcul()" /><br />
<br />
</form>

<strong>The Net Income of Balfour Betty plc is </strong><span id="NetIncome">XXX</span>
<strong> million</strong><br />
<br />
<strong>The addition to retained earnings of Balfour Betty plc is </strong><span id="AtRE">
XXX</span><strong> million</strong>
<br />
<br />

第一个问题:四舍五入。以下答案:<span id="NetIncome">需要动态舍入。我尝试添加一个名为的新变量RNetInc并添加以下等式RNetInc = NetInc.toFixed(4),但它只给了我两位小数,刷新后它甚至不再起作用。将答案四舍五入为 N 个小数的最佳方法是什么?

第二个问题是我不知道这是否可能。我想到的是以下内容:下拉菜单

<select>
    <option value"1">1 decimal</option>
    <option value"2">2 decimals</option>
    <option value"3">3 decimals</option>
</select> 

所以,我想要的是,当我点击 时N decimal,答案将变为 N 小数。这是一个非常复杂的情况,但我经常需要。

因为我只知道 Javascript 的(非常)基础知识,所以即使使用谷歌我也找不到答案。有人可以让我走上正确的轨道(如果可能的话)?提前致谢。

4

1 回答 1

1

我建议只修复最终结果,toFixed()返回一个字符串。

HTML 用于select

<select id="dec">
    <option value="1">1 decimal</option>
    <option value="2">2 decimals</option>
    <option value="3">3 decimals</option>
</select>

calcul()

var decs = +(document.getElementById('dec').value); // Add this line
document.getElementById("NetIncome").innerHTML = (TaxInc - ((TaxR / 100) * TaxInc)).toFixed(decs);
document.getElementById("AtRE").innerHTML = (NetInc - Divid).toFixed(decs);

jsFiddle 的现场演示(更新)。

编辑

看起来我部分误解了你的问题。请检查更新的小提琴,现在您还可以随时通过从 中选择一个值来更改小数位数select

于 2013-08-15T19:53:57.960 回答