JavaScript- HTML数字输入点验证

Question

我有一个输入
和java脚本函数如下，但是当用户输入多个点时，obj.val总是返回空字符串，因此我无法限制用户从第二个点开始。我有几个使用此功能的输入，所以我需要修改功能。

＆＃13;

＆＃13;

function restrictChars(e, obj)
    {
        var CHAR_AFTER_DP = 2;  // number of decimal places
        var validList = "0123456789.";  // allowed characters in field
        var key, keyChar;
        key = getKey(e);
        if (key == null) return true;
        // control keys
        // null, backspace, tab, carriage return, escape
        if ( key==0 || key==8 || key==9 || key==27 )
            return true;
        // get character
        keyChar = String.fromCharCode(key);
        // check valid characters
        if (validList.indexOf(keyChar) != -1)
        {
            // check for existing decimal point
            var dp = 0;
            if( (dp = obj.value.indexOf( ".")) > -1)
            {
            if(keyChar == "." && dotCheck == 0)
            {                 
                return false;                // only one allowed
            }
            
            else
            {
                // room for more after decimal point?
                if( obj.value.length - dp <= CHAR_AFTER_DP)
                return true;
            }

            dotCheck++;
        }
        else 
            return true;
        }
        // not a valid character
        return false;
    }
function getKey(e)
    {
        if (window.event)
            return window.event.keyCode;
        else if (e)
            return e.which;
        else
            return null;
    }

＆＃13;

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<input type='number' class='ui-input-text ui-body-a' maxlength='3' id='txtP' step="1"  style='text-align:right;width: 50px' name='name1' onkeypress="return restrictChars(event, this)" />

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＆＃13;

＆＃13;