CSS

.popup_tooltip {
    position: absolute;
    z-index: 999;
    left: -9999px;
    background-color: #222;
    padding: 5px 10px;
    width: 250px;
    color: #fff;
    border-radius: 5px;
}
.popup_tooltip p {
    margin: 0;
}

JS

function simple_tooltip(target_items, name){
    $(target_items).each(function(i){
        $("body").append("<div class='popup_"+name+"' id='" + name + i + "'><p>" + $(this).attr('title') + "</p></div>");
        var my_tooltip = $("#" + name + i);

        $(this).removeAttr("title").mouseover(function(){
            my_tooltip.css({opacity: 0.8, display: "none"}).fadeIn(400);
        }).mousemove(function(kmouse){
            my_tooltip.css({left: kmouse.pageX + 15, top: kmouse.pageY + 15});
        }).mouseout(function(){
            my_tooltip.fadeOut(400);
        });
    });
}
// Использовать так:
$(document).ready(function(){
    simple_tooltip("a.tooltip", "tooltip");
});
jQuery.fn.ForceNumericOnly = function() {
    return this.each(function() {
        jQuery(this).keydown(function(e) {
            var key = e.charCode || e.keyCode || 0;
            // allow backspace, tab, delete, enter, arrows, numbers and keypad numbers ONLY
            // home, end, period, and numpad decimal
            return (
                key == 8 || 
                key == 9 ||
                key == 13 ||
                key == 46 ||
                key == 110 ||
                key == 190 ||
                (key >= 35 && key <= 40) || (key >= 48 && key <= 57) || (key >= 96 && key <= 105));
        });
    });
};

Использовать так:

jQuery(document).ready(function($){
    $("#yourTextBoxName").ForceNumericOnly();
});

Источник: https://stackoverflow.com/questions/995183/how-to-allow-only-numeric-0-9-in-html-inputbox-using-jquery

Спецсимволы HTML