Pre populate a text input field

Question

I have a number of text input fields in an event registration channel that I would like to be pre-poulated with defaults and so not require entering anything unless it's different. This thread gives the javascript to add in the instructions box for Matrix fields, but I want it for a single Text input field and my javascript is rubbish.

Answer 1

Since Field Instructions will allow HTML and JS, you can add the following in the Field Instructions for that custom field:

<script type="text/javascript">
    $(document).ready(function() {
        if ($('#field_id_23').is(':empty')) {
            $('#field_id_23').val('This is the default text');
        }
    });
</script>

Just be sure to change field_id_23 to the correct field_id in your instance.

Important note: If you are entering this snippet in a custom field's Field Instructions make sure it does not use space characters for the indentation. If you copy and paste directly from here it will and they will be encoded to   which will break the JS.

As an alternative to using Field Instructions to hold your JavaScript, CP CSS & JS is useful for adding snippets of JS to the Control Panel.

---

Note that the above jQuery assumes you would never want to leave the text input blank. If that isn't the case, you'll want to incorporate a check that this is a new entry instead of relying on the .is(':empty') conditional:

<script type="text/javascript">
    $(document).ready(function() {
        if ($('input[name="entry_id"]').val() == '0') {
            $('#field_id_23').val('This is the default text');
        }
    });
</script>