I am looking to find the parent div id (i.e. \"Bakerloo\") from this layout when the button is clicked within \".buttonleft0\" in jquery / javascript.
Your code itself have few errors so here is the correct one:
HTML
<div id='Bakerloo' class='box'>bakerloo<p></p><span class='buttons'>
<span class='buttonleft0'><button><span class='icon icon10'>Click here</span>
</button>
</span><span class='buttonleft'></span><span class='buttonright'></span></span>
<div class='comingup'></div>
<div class='more'></div></div>
JQuery
jQuery(document).ready(function($){
$("button").on('click',function(){
alert($(this).closest('div').attr('id'));
});
});
here is the fiddle http://jsfiddle.net/cpeeyush/ydk4e/