只需添加step="。01”，整理了我的问题。

<input type="number" class="form-control" name="price" step=".01">

如果有人正在寻找一个正则表达式，只允许数字与可选的2小数点后

^\d*(\.\d{0,2})?$

例如，我发现下面的解决方案相当可靠

HTML:

<input name="my_field" pattern="^\d*(\.\d{0,2})?$" />

JS / JQuery:

$(document).on('keydown', 'input[pattern]', function(e){
  var input = $(this);
  var oldVal = input.val();
  var regex = new RegExp(input.attr('pattern'), 'g');

  setTimeout(function(){
    var newVal = input.val();
    if(!regex.test(newVal)){
      input.val(oldVal); 
    }
  }, 1);
});

关于货币，我建议:

<div><label>Amount $
    <input type="number" placeholder="0.00" required name="price" min="0" value="0" step="0.01" title="Currency" pattern="^\d+(?:\.\d{1,2})?$" onblur="
this.parentNode.parentNode.style.backgroundColor=/^\d+(?:\.\d{1,2})?$/.test(this.value)?'inherit':'red'
"></label></div>

参见http://jsfiddle.net/vx3axsk5/1/

HTML5属性“step”，“min”和“pattern”将在表单提交时验证，而不是onblur。如果你有一个模式，你就不需要步骤，如果你有一个步骤，你就不需要模式。因此，您可以使用我的代码返回到step="any"，因为模式无论如何都会验证它。

If you'd like to validate onblur, I believe giving the user a visual cue is also helpful like coloring the background red. If the user's browser doesn't support type="number" it will fallback to type="text". If the user's browser doesn't support the HTML5 pattern validation, my JavaScript snippet doesn't prevent the form from submitting, but it gives a visual cue. So for people with poor HTML5 support, and people trying to hack into the database with JavaScript disabled or forging HTTP Requests, you need to validate on the server again anyways. The point with validation on the front-end is for a better user experience. So as long as most of your users have a good experience, it's fine to rely on HTML5 features provided the code will still works and you can validate on the back-end.

使用这段代码

<input type="number" step="0.01" name="amount" placeholder="0.00">

HTML5 Input元素的默认Step值为Step ="1"。

步骤1:将HTML数字输入框与onchange事件挂钩

myHTMLNumberInput.onchange = setTwoNumberDecimal;

或者HTML代码

<input type="number" onchange="setTwoNumberDecimal" min="0" max="10" step="0.25" value="0.00" />

步骤2:编写setTwoDecimalPlace方法

function setTwoNumberDecimal(event) {
    this.value = parseFloat(this.value).toFixed(2);
}

您可以通过改变传递给toFixed()方法的值来改变小数点后的位数。请参阅MDN文档。

toFixed(2); // 2 decimal places
toFixed(4); // 4 decimal places
toFixed(0); // integer

使用Javascript在文本框中只输入3个小数点。

<input type="text" class="form-control" onkeypress='return AllowOnlyAmountAndDot(this,event,true);/>

function AllowOnlyAmountAndDot(id, e, decimalbool) {    
    if(decimalbool == true) {   
        var t = id.value;
        var arr = t.split(".");
        var lastVal = arr.pop();
        var arr2 = lastVal.split('');
        if (arr2.length > '2') {
            e.preventDefault();
        } 
    }
}