You have a lookup field in a table. And when adding a new record to the table, you want that field to be set to the first value by default (rather than being empty).
Add the following code to hooks/tablename-dv.js
(where tablename is the name of the concerned table).
If the file doesn't exist, create it.
$j(function() {
// Run this code only if this is a new record
if($j('[name=SelectedID]').val().length) return;
setTimeout(function() {
$j.ajax({
url: 'ajax_combo.php',
data: {
s: '',
p: 1,
t: 'tablename',
f: 'lookup_fieldname'
},
success: function(data) {
if(data.results.length < 2) return;
$j('#lookup_fieldname-container').select2('data', data.results[1]);
}
})
}, 1000); // this delay might be necessary to ensure all select2 is loaded first
})
Change tablename
and lookup_fieldname
above to the actual table name and lookup field name.