jQuery Restricting certain numbers from being typed in a Bootstrap input

Question

Okay, I did a mistake and blindly copied and pasted a ''code snippet' that is supposed to restrict the user from typing down ANYTHING ELSE other than a number in a Bootstrap input field.

By blindly doing that, i did not really understood how it's supposed to work. Now i need to allow the decimal point, the "." to be typed down and i don't know what i need to change.

Can someone explain the snippet below or provide a resource?

$('#elementXPosition,#elementYPosition,#elementWidth,#elementHeight').keypress(function(e) {
    var a = [];
    var k = e.which;

    for (i = 48; i < 58; i++)
        a.push(i);

    if (!(a.indexOf(k)>=0))
        e.preventDefault();

});

Answer 1

Here is the solution I am able to create for you
There are two possible solutions to go with and I would prefer to go with HTML's pattern feature.

**HTML**  
<input type="text" id="elementXPosition" pattern="[0-9.]+" title="Please enter decimal numbers only" placeholder="Using pattern" />
<input type="text" id="elementYPosition" placeholder="Using jQuery" />  

**jQuery**  
$(document).ready(function () {
    $("#elementYPosition").keydown(function (e) {
        /*To check if shift key was pressed*/
        if (e.shiftKey == true) {
            e.preventDefault();
        }
        /*Allows some keys to be pressed*/
        if ((e.keyCode >= 48 && e.keyCode <= 57) || (e.keyCode >= 96 && e.keyCode <= 105) || e.keyCode == 8 || e.keyCode == 9 || e.keyCode == 37 || e.keyCode == 39 || e.keyCode == 46 || e.keyCode == 190) {} else {
            e.preventDefault();
        }
        /*This will allow the '.' to be pressed only once*/
        if ($(this).val().indexOf('.') !== -1 && e.keyCode == 190) e.preventDefault();

    });
});  

Also here is the list of key codes you might need to edit the code as per your wish.
Hopefully it helps.