In javascript, we can use setTimeout to do call itself recursively until a condition is met.
Here, we want to check the html content with an interval of 300ms until it is populated, then we will do something.
function checkPostCode() { if ($('#my_postcode').html() == '') { setTimeout(function() { checkPostCode(); }, 300); } else { $('#nearest_store').html('some content'); return; } } checkPostCode();