Jquery mobile loses custom style after button text changed - jquery-mobile

Question

I have a simple (newbie here) task in jquery mobile. Change the text of a button which has a custom style applied. I can change the text without problem in the 'pageinit' event however I lose the custom style in the process. Have read lots of article in stackoverflow but still lack a working solution.
Excerpt of html page below loaded by ajax
CSS
#goal .ui-btn-inner {
text-align: center;
background: chartreuse;
ui-disabled: true;
}
Button to be styled
<div data-corners="false" data-role="controlgroup" >
<a href="#" data-role="button" id="goal" >
text to be changed
</a>
</div>
...
Here is the jquery mobile code that changes the button text.
$(document).delegate('#problem_screen', 'pageinit', function() {
$('#goal').on('click', function() {
console.log('goal clicked');
});
$('#goal .ui-btn-text').text('New button text');
});
Thanks

Answer 1

Finally got this to work. My first JQM mistake was to define custom styles on each page of the multiple page application. This is wrong -- you must define all your custom styles in one location, typically a style sheet file which is included by every page. Another mistake is to have same id value on different pages. Wrong -- id values must be unique throughout application.
The api that applies (in this case enhances a style) is .addClass("). In my case I defined a style as follows:
.goal-style {
text-align: center;
background: charteuse;
ui-disabled: true;
}
Now after I update the button's text I say:
$('#goal').addClass('goal-style'); // Note: do not use '.goal-style'