Data not passing via JQuery AJAX request

Question

I am frustrated with this and can't get the data to pass. Firebug has been showing me

letter=

I have tried

data: {letter: alpha},

AND

data:"letter=" + alpha, 

with no success.

Script below:

$(document).ready(function(){
    $('#alphaFilter a').click(function(e){
        e.preventDefault();
        var alpha = $(this).val();
        $.ajax({
            type: "POST",
            data: {letter: alpha},
            url: "includes/filterPlants.php",
            success: function(update){
                $('#plants').html(update);
            }
        });
    });
})

My HTML element below (basically I want to filter the data set without page refresh):

<div id="alphaFilter">
    <a href="#" value="All">All</a>
    <a href="#" value="A">A</a>
    <a href="#" value="B">B</a>
    <a href="#" value="C">C</a>
    <a href="#" value="D">D</a>
    <a href="#" value="E">E</a>
    <a href="#" value="F">F</a>
    <a href="#" value="G">G</a>
    <a href="#" value="H">H</a>
    <a href="#" value="I">I</a>
    <a href="#" value="J">J</a>
    <a href="#" value="K">K</a>
    <a href="#" value="L">L</a>
    <a href="#" value="M">M</a>
    <a href="#" value="N">N</a>
    <a href="#" value="O">O</a>
    <a href="#" value="P">P</a>
    <a href="#" value="Q">Q</a>
    <a href="#" value="R">R</a>
    <a href="#" value="S">S</a>
    <a href="#" value="T">T</a>
    <a href="#" value="U">U</a>
    <a href="#" value="V">V</a>
    <a href="#" value="W">W</a>
    <a href="#" value="X">X</a>
    <a href="#" value="Y">Y</a>
    <a href="#" value="Z">Z</a>
</div>

Thanks in advance, I'm sure this is a pretty easy one for you guys.

Answer 1

value attributes and jQuery's .val() are only really meant for <form> elements like <input> s.

For other element types, you can use data-* attributes to store custom information:

<a href="#" data-value="A">A</a>

And retrieve their values with jQuery's .data() :

var alpha = $(this).data('value');

Answer 2

I believe your HTML is invalid (I don't believe the anchor tag supports a value attribute). In addition, the jQuery val method won't grab the contents of the value attribute inside your anchor tag.

If you want, you can use the HMLT5 data-* attribute:

<a href="#" data-value="A">A</a>

$(function(){

    $('#alphaFilter a').click(function(e){
        e.preventDefault();
        var alpha = $(this).attr('data-value');

        $.ajax({
            type: "POST",
            data: {letter: alpha},
            url: "includes/filterPlants.php",
            success: function(update){
                $('#plants').html(update);
            }
        });

    });

})

EDIT

As it has been pointed out in the comments, the jQuery .data() method will work for this purpose as well. Both of these will grab the value of "data-value":

$(this).data("value");

//or

$(this).attr("data-value");

Answer 3

var alpha = $(this).attr("value")