js实现只能输入俩位小数的文本框（在输入时进行控制）

1 function inputCheck(obj){
2             if (null == event) {
3                 event = window.event;
4             }
5             var keyCode = event.keyCode;
6             var key =  (keyCode);
7             if( keyCode < 48 && keyCode != 46  || keyCode > 57 ){
8                 event.returnValue = false;
9             }
10             var value = $(obj).val();
11             var valueStr = value.toString();
12             var dotPosition = valueStr.indexOf(".");
13             if(keyCode == 46){
14                 if(valueStr == ""){
15                     event.returnValue = false;
16                 }
17                 if(dotPosition > -1 ){
18                     event.returnValue = false;
19                 }
20             }
21             if(dotPosition > -1){
22                 var dotLength = valueStr.substr(dotPosition + 1).length;
23                 if(dotLength >= 2){
24                     var position = getPosition(obj);
25                     if(position > dotPosition){
26                         event.returnValue = false;
27                     }
28                 }
29             }
30         }
31          function getPosition(obj){
32             var result = 0;
33             if(obj.selectionStart){ //非IE浏览器
34                result = obj.selectionStart
35             }else{ //IE
36                var rng;
37                if(obj.tagName == "TEXTAREA"){ //如果是文本域
38                 rng = event.srcElement.createTextRange();
39                 rng.moveToPoint(event.x,event.y);
40                }else{ //输入框
41                 rng = document.selection.createRange();
42                }
43                rng.moveStart("character",-event.srcElement.value.length);
44                result = rng.text.length;
45             }
46             return result;
47         }

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