從多個下拉選擇列表中的最小值，如math.min

Question

我想弄清楚如何實現這...我有三個下拉選擇列表，每個列表都有自己的值分配。我希望將三個選定值中的最小值/最小值轉換爲隱藏/禁用的文本字段（並且還可以顯示在列表下）。

這裏就是我想要一起工作： -

<select name="Question1" id="Question1" onchange="code(1)"> 
<option value="10.00" >This is answer A1</option> 
<option value="20.00" >This is answer A2</option> 
<option value="30.00" >This is answer A3</option> 
</select> 

<select name="Question2" id="Question2" onchange="code(2)"> 
<option value="10.00" >This is answer B1</option> 
<option value="20.00" >This is answer B2</option> 
<option value="30.00" >This is answer B3</option> 
</select> 

<select name="Question3" id="Question3" onchange="code(3)"> 
<option value="10.00" >This is answer C1</option> 
<option value="20.00" >This is answer C2</option> 
<option value="30.00" >This is answer C3</option> 
</select> 

<input type="text" id="LowestValue" name="LowestValue" onfocus="this.blur()" /> 

<p>The lowest value is <span>//here should be the lowest of three values</span></p> 

所以用戶選擇30.00，30.00和10.00的結果應該是10.00如果是有道理的？

<script> 
    function code() { // forget the parameter 
    var Value1 = document.getElementById('Question1'); 
    var Value2 = document.getElementById('Question2'); 
    var Value3 = document.getElementById('Question3'); 
    var LowestValue = document.getElementById('LowestValue'); 

//I realise this below is wrong but this is essentially what I'm hoping to acheive... 
//var total = Math.min(Value1, Value2, Value3); 

LowestValue.value = total; 
} 
</script> 

的值是十進制（雙），因爲數值來表示貨幣價值（£10.00）

JSFiddle

感謝您的時間:)

Answer 1

這裏更新的示例代碼：http://jsfiddle.net/2qae6r52/5/

在小提琴
• LowestValueOutput ID添加到span
• 使用
• unwrapped the function declaration of codeselect的.value元件
• 使用3個參數來Math.min
• 附加disabled屬性的最後輸入
• 使用.textContent爲span content
• use .toFixed(2) for make a string wi第2位小數（由Math.floor選中）

這裏的HTML代碼：

<select name="Question1" id="Question1" onchange="code(1)"> 
    <option value="10.00" >This is answer A1</option> 
    <option value="20.00" >This is answer A2</option> 
    <option value="30.00" >This is answer A3</option> 
</select> 

<select name="Question2" id="Question2" onchange="code(2)"> 
    <option value="10.00" >This is answer A1</option> 
    <option value="20.00" >This is answer A2</option> 
    <option value="30.00" >This is answer A3</option> 
</select> 

<select name="Question3" id="Question3" onchange="code(3)"> 
    <option value="10.00" >This is answer A1</option> 
    <option value="20.00" >This is answer A2</option> 
    <option value="30.00" >This is answer A3</option> 
</select> 

<input type="text" disabled="disabled" id="LowestValue" name="LowestValue" onfocus="this.blur()" /> 

<p>The lowest value is <span id="LowestValueOutput"><!--here should be the lowest of three values--></span></p> 

這裏的JS代碼：

function code() { // forget the parameter 
    var Value1 = document.getElementById('Question1'); 
    var Value2 = document.getElementById('Question2'); 
    var Value3 = document.getElementById('Question3'); 
    var LowestValue = document.getElementById('LowestValue'); 
    var LowestValueOutput = document.getElementById('LowestValueOutput'); 

    var total = Math.min(Value1.value, Value2.value, Value3.value); 
    if (total != Math.floor(total)) { 
     total = total.toFixed(2); 
    } 

    LowestValue.value = LowestValueOutput.textContent = total; 
} 

Answer 2

window.onload=function() { 
    var sel1 = document.getElementById('Question1'), 
     sel2 = document.getElementById('Question2'), 
     sel3 = document.getElementById('Question3'), 
     lowest =document.getElementById('LowestValue'); 
    sel1.onchange= 
    sel2.onchange= 
    sel3.onchange=function() { 
    lowest.value=Math.min(
    parseFloat(sel1.value), 
    parseFloat(sel2.value), 
    parseFloat(sel3.value)).toFixed(2); 
    } 
}