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);
});

在输入文本中放入一个类，并将其命名为only_numbers

把jquery代码放在页面中

$(document).ready(function() {
    $('.only_numbers').keyup(function() {
        var numbers = $(this).val();
        $(this).val(numbers.replace(/\D/, ''));
    });
});

玩得开心:-)

jQuery("#no_of").keypress(function(event){
    //Allow only backspace and delete
    if (event.keyCode != 46 && event.keyCode != 8) {
        if (!parseInt(String.fromCharCode(event.which))) {
            event.preventDefault();
        }
    }
});

jQuery("#no_of").keyup(function(e){
    var temp_s= jQuery("#no_of").val();
    var multiply_val= temp_s*10;
    jQuery("#ex-r").html(multiply_val);
});

用这种形式。在我看来，允许home, end, shift和ctrl这样的键是正确的，缺点是用户可以打印特殊字符:

$("#busca_cep").keydown(function(event) {
    if ( event.keyCode == 46 || event.keyCode == 8 || event.keyCode == 13 || event.keyCode == 16 || event.keyCode == 36 || event.keyCode == 35) {
        if (event.keyCode == 13) {
            localiza_cep(this.value);
        }
    } else {
        if ((event.keyCode < 48 || event.keyCode > 57) && (event.keyCode < 96 || event.keyCode > 105 )) {
            event.preventDefault(); 
        }   
    }
});

/**
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。

这是我不久前创建的一个快速解决方案。你可以在我的文章中了解更多:

http://ajax911.com/numbers-numeric-field-jquery/

$("#textfield").bind("keyup paste", function(){
    setTimeout(jQuery.proxy(function() {
        this.val(this.val().replace(/[^0-9]/g, ''));
    }, $(this)), 0);
});