用Jquery控制文本框只能输入数字和字母

$.fn.onlyNum = function () {
    $(this).keypress(function (event) {
        var eventObj = event || e;
        var keyCode = eventObj.keyCode || eventObj.which;
        if ((keyCode >= 48 && keyCode <= 57) || ((keyCode == 8 || keyCode == 46)))
            return true;
        else
            return false;
    }).focus(function () {
        //禁用输入法
        this.style.imeMode = ‘disabled‘;
    });
};