你可以像这样使用on input事件:

$(document).on("input", ".numeric", function() {
    this.value = this.value.replace(/\D/g,'');
});

但是，这个代码特权是什么?

它适用于移动浏览器(keydown和keyCode有问题)。 它也适用于AJAX生成的内容，因为我们使用了“on”。 比按下键更好的性能，例如在粘贴事件上。

$(document).ready(function() {
    $("#txtboxToFilter").keydown(function(event) {
        // Allow only backspace and delete
        if ( event.keyCode == 46 || event.keyCode == 8 ) {
            // let it happen, don't do anything
        }
        else {
            // Ensure that it is a number and stop the keypress
            if (event.keyCode < 48 || event.keyCode > 57 ) {
                event.preventDefault(); 
            }   
        }
    });
});

来源:http://snipt.net/GerryEng/jquery-making-textfield-only-accept-numeric-values

这将在添加非数字字符时保持先前的值。

$(document).on('input', '.digit-input', function() {
    var prevVal = $(this).attr('ov') ? $(this).attr('ov') : '';
    var newVal = this.value.replace(/[^0-9]/g, '');
    this.value = newVal != '' ? newVal : prevVal;
    $(this).attr('ov', this.value);
});

$(文件)。据(’input’'。digit-input'，函数(){ var prevVal = $(this).attr('ov') ?$(this).attr('ov'): "; var newVal = this.value。回想起(^ [0 - 9]/ g '); this。= = " ? "newVal: prevVal; $ (this)。attr(’ov’this.value); }); < script " src = " https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js " > / < script > <input type="text" class=" digital -input">

没有一个答案在我的情况下工作，所以我在接受的答案做了一点改变，使它为动态添加的元素工作。

享受:

var inputFilter = function (elem, cb) {
    /*
    *    /^-?\d*$/               restricts input to integer numbers
    *    /^\d*$/                 restricts input to unsigned integer numbers
    *    /^[0-9a-f]*$/i          restricts input to hexadecimal numbers
    *    /^-?\d*[.,]?\d*$/       restricts input to floating point numbers (allowing both . and , as decimal separator)
    *    /^-?\d*[.,]?\d{0,2}$/   restricts input to currency values (i.e. at most two decimal places)
    */
    bdy.on('input keydown keyup mousedown mouseup select contextmenu drop', elem, function () {
        if (cb(this.value)) {
            this.oldValue = this.value;
            this.oldSelectionStart = this.selectionStart;
            this.oldSelectionEnd = this.selectionEnd;
        } else if (this.hasOwnProperty('oldValue')) {
            this.value = this.oldValue;
            this.setSelectionRange(this.oldSelectionStart, this.oldSelectionEnd);
        }
    });
};

用法:

inputFilter('#onlyDigitsInput', function (val) {
    return /^\d*$/.test(val);
});

/**
Makes the textbox to accept only numeric input
*/

(function($) {
    $.fn.allowOnlyNumeric = function() {

        /**
        The interval code is commented as every 250 ms onchange of the textbox gets fired.
        */

        //  var createDelegate = function(context, method) {
        //      return function() { method.apply(context, arguments); };
        //  };

        /**
        Checks whether the key is only numeric.
        */
        var isValid = function(key) {
            var validChars = "0123456789";
            var validChar = validChars.indexOf(key) != -1;
            return validChar;
        };

        /**
        Fires the key down event to prevent the control and alt keys
        */
        var keydown = function(evt) {
            if (evt.ctrlKey || evt.altKey) {
                evt.preventDefault();
            }
        };

        /**
        Fires the key press of the text box   
        */
        var keypress = function(evt) {
            var scanCode;
            //scanCode = evt.which;
            if (evt.charCode) { //For ff
                scanCode = evt.charCode;
            }
            else { //For ie
                scanCode = evt.keyCode;
            }

            if (scanCode && scanCode >= 0x20 /* space */) {
                var c = String.fromCharCode(scanCode);
                if (!isValid(c)) {
                    evt.preventDefault();
                }
            }
        };

        /**
        Fires the lost focus event of the textbox   
        */
        var onchange = function() {
            var result = [];
            var enteredText = $(this).val();
            for (var i = 0; i < enteredText.length; i++) {
                var ch = enteredText.substring(i, i + 1);
                if (isValid(ch)) {
                    result.push(ch);
                }
            }
            var resultString = result.join('');
            if (enteredText != resultString) {
                $(this).val(resultString);
            }

        };

        //var _filterInterval = 250;
        //var _intervalID = null;

        //var _intervalHandler = null;

        /**
        Dispose of the textbox to unbind the events.
        */
        this.dispose = function() {
            $(this).die('change', onchange);
            $(this).die('keypress', keypress);
            $(this).die('keydown', keydown);
            //window.clearInterval(_intervalHandler);
        };

        $(this).live('change', onchange);
        $(this).live('keypress', keypress);
        $(this).live('keydown', keydown);
        //_intervalHandler = createDelegate(this, onchange);
        //_intervalID = window.setInterval(_intervalHandler, _filterInterval);
    }
})(jQuery);

上面的$ plugin是从AjaxControlToolkit过滤器文本框extender.js编写的。

然而，有一个行为并没有从AjaxControlToolkit中借用，那就是当用户复制和粘贴任何非数字值时，onchange事件就会触发，文本框就会吞噬这些值。我检查了代码，发现这个onchange在每250ms之后被调用，这是一个性能打击，因此注释了这部分。

使用下面简单的jQuery，在文本框中只允许数字字符。您不需要手动筛选所有特殊字符，因此不会有遗漏某些特殊字符的危险。这将只允许数字0-9:(将下面的代码放在document ready中，并根据您的数字文本字段类名更改类名。)

//Event of data being keyed in to textbox with class="numericField".
$(".numericField").keyup(function() {
    // Get the non Numeric char that was enetered
    var nonNumericChars = $(this).val().replace(/[0-9]/g, '');                                  
    // Now set the value in text box 
    $(this).val( $(this).val().replace(nonNumericChars, ''));    

});