项目需要能步进小数点的数字输入框，但是mui 的数字输入框只能步进整数，发现只要把 源码中的parseInt 改成 parseFloat 就行了，可是后来新的问题又出现了,
浮点数进行加减的精确问题，这是所有编程语言都有的.
下面是完美解决方案，只需将mui.js中关于数字输入框的源代码改成如下即可，mui.js中的位置大概在8158行左右
1 /**
2 * 数字输入框
3 * varstion 1.0.1
4 * by Houfeng
5 * Houfeng@DCloud.io
6 */
7
8 (function($) {
9
10 var touchSupport = ('ontouchstart' in document);
11 var tapEventName = touchSupport ? 'tap' : 'click';
12 var changeEventName = 'change';
13 var holderClassName = 'mui-numbox';
14 var plusClassSelector = '.mui-btn-numbox-plus,.mui-numbox-btn-plus';
15 var minusClassSelector = '.mui-btn-numbox-minus,.mui-numbox-btn-minus';
16 var inputClassSelector = '.mui-input-numbox,.mui-numbox-input';
17
18
19 this.floatAdd=function(arg1, arg2){
20 var r1, r2, m, c;
21 try {
22 r1 = arg1.toString().split(".")[1].length;
23 }
24 catch (e) {
25 r1 = 0;
26 }
27 try {
28 r2 = arg2.toString().split(".")[1].length;
29 }
30 catch (e) {
31 r2 = 0;
32 }
33 c = Math.abs(r1 - r2);
34 m = Math.pow(10, Math.max(r1, r2));
35 if (c > 0) {
36 var cm = Math.pow(10, c);
37 if (r1 > r2) {
38 arg1 = Number(arg1.toString().replace(".", ""));
39 arg2 = Number(arg2.toString().replace(".", "")) * cm;
40 } else {
41 arg1 = Number(arg1.toString().replace(".", "")) * cm;
42 arg2 = Number(arg2.toString().replace(".", ""));
43 }
44 } else {
45 arg1 = Number(arg1.toString().replace(".", ""));
46 arg2 = Number(arg2.toString().replace(".", ""));
47 }
48 return (arg1 + arg2) / m;
49 },
50 this.floatSub=function(arg1,arg2){
51 var r1, r2, m, n;
52 try {
53 r1 = arg1.toString().split(".")[1].length;
54 }
55 catch (e) {
56 r1 = 0;
57 }
58 try {
59 r2 = arg2.toString().split(".")[1].length;
60 }
61 catch (e) {
62 r2 = 0;
63 }
64 m = Math.pow(10, Math.max(r1, r2)); //last modify by deeka //动态控制精度长度
65 n = (r1 >= r2) ? r1 : r2;
66 return ((arg1 * m - arg2 * m) / m).toFixed(n);
67 }
68
69 var _this=this;
70 var Numbox = $.Numbox = $.Class.extend({
71 /**
72 * 构造函数
73 **/
74 init: function(holder, options) {
75 var self = this;
76 if (!holder) {
77 throw "构造 numbox 时缺少容器元素";
78 }
79 self.holder = holder;
80 options = options || {};
81 options.step = parseFloat(options.step || 1);
82 self.options = options;
83 self.input = $.qsa(inputClassSelector, self.holder)[0];
84 self.plus = $.qsa(plusClassSelector, self.holder)[0];
85 self.minus = $.qsa(minusClassSelector, self.holder)[0];
86 self.checkValue();
87 self.initEvent();
88 },
89 /**
90 * 初始化事件绑定
91 **/
92 initEvent: function() {
93 var self = this;
94 self.plus.addEventListener(tapEventName, function(event) {
95 // var val = parseFloat(self.input.value) + self.options.step;
96 var val=_this.floatAdd(parseFloat(self.input.value),self.options.step);
97 self.input.value = val.toString();
98 $.trigger(self.input, changeEventName, null);
99 });
100 self.minus.addEventListener(tapEventName, function(event) {
101 // var val = parseFloat(self.input.value) - self.options.step;
102 var val=_this.floatSub(parseFloat(self.input.value),self.options.step);
103 self.input.value = val.toString();
104 $.trigger(self.input, changeEventName, null);
105 });
106 self.input.addEventListener(changeEventName, function(event) {
107 self.checkValue();
108 var val = parseFloat(self.input.value);
109 //触发顶层容器
110 $.trigger(self.holder, changeEventName, {
111 value: val
112 });
113 });
114 },
115 /**
116 * 获取当前值
117 **/
118 getValue: function() {
119 var self = this;
120 return parseFloat(self.input.value);
121 },
122 /**
123 * 验证当前值是法合法
124 **/
125 checkValue: function() {
126 var self = this;
127 var val = self.input.value;
128 if (val == null || val == '' || isNaN(val)) {
129 self.input.value = self.options.min || 0;
130 self.minus.disabled = self.options.min != null;
131 } else {
132 var val = parseFloat(val);
133 if (self.options.max != null && !isNaN(self.options.max) && val >= parseFloat(self.options.max)) {
134 val = self.options.max;
135 self.plus.disabled = true;
136 } else {
137 self.plus.disabled = false;
138 }
139 if (self.options.min != null && !isNaN(self.options.min) && val <= parseFloat(self.options.min)) {
140 val = self.options.min;
141 self.minus.disabled = true;
142 } else {
143 self.minus.disabled = false;
144 }
145 self.input.value = val;
146 }
147 },
148 /**
149 * 更新选项
150 **/
151 setOption: function(name, value) {
152 var self = this;
153 self.options[name] = value;
154 },
155 /**
156 * 动态设置新值
157 **/
158 setValue: function(value) {
159 this.input.value = value;
160 this.checkValue();
161 }
162
163 });
164
165 $.fn.numbox = function(options) {
166 var instanceArray = [];
167 //遍历选择的元素
168 this.each(function(i, element) {
169 if (element.numbox) {
170 return;
171 }
172 if (options) {
173 element.numbox = new Numbox(element, options);
174 } else {
175 var optionsText = element.getAttribute('data-numbox-options');
176 var options = optionsText ? JSON.parse(optionsText) : {};
177 options.step = element.getAttribute('data-numbox-step') || options.step;
178 options.min = element.getAttribute('data-numbox-min') || options.min;
179 options.max = element.getAttribute('data-numbox-max') || options.max;
180 element.numbox = new Numbox(element, options);
181 }
182 });
183 return this[0] ? this[0].numbox : null;
184 }
185
186 //自动处理 class='mui-locker' 的 dom
187 $.ready(function() {
188 $('.' + holderClassName).numbox();
189 });
190
191 }(mui));