Change a buttons value if parameters are met, jQuery, PHP, Sessions - php

Question

I have the following button:
<input type="button" count='<?php echo count($_SESSION['children']);?>' name="children" class="add_child" value="Add Another Child"/>
On default when the form loads (with a clean session) there is no input for children, so the button should read "Add a Child".
If there is a text field present with the name children[] then it should just display: "Add another Child".
How would this be done ?
I am using php / jquery / sessions for the fields here is the code for it:
$('.add_child').click(function(){
var attrName = $(this).attr('name');
var count = $(this).attr('count');
$(this).attr('count', (parseInt(count)+1))
var input = $('<input />');
input.attr('type','text')
input.attr('name',attrName+"["+count+"]" )
$('.children_form').append($('<li />').append(input));
$('#content li:odd').addClass('alt');
})
<?php
if(isset($_SESSION['children'])) {
foreach($_SESSION['children'] as $index=>$child){ ?>
<li>
<?php echo "<input type='text' name='children[{$index}]' value='{$child}'/>";?>
</li>
<?php } }?>

Answer 1

Try this out with the code you have already:
$('.add_child').click(function(){
//code...
$(this).val('Add Another Child');
})
and the php for the input:
<input type="button" count='<?php echo count($_SESSION['children']);?>'
name="children" class="add_child"
value="<?php echo (isset($_SESSION['children'])?
'Add Another Child':'Add a Child');?>"
/>