@Michael_Kim_shc
Out of the box, all Tags loading via Tealium will fire at DOM Ready.
You can change this setting to DOM Complete, but you cannot have both DOM Ready and DOM Complete, you gotta pick one. You will want a JavaScript Extension scoped to PreLoader with the following code:
window.utag_cfg_ovrd = window.utag_cfg_ovrd || {};
utag_cfg_ovrd.dom_complete = true;
Now that said, there is one other setting called the wait flag which is set on a tag by tag basis. For each tag where the wait flag is no, that tag will load as soon as possible and will not wait for DOM state to change.
You can read more about the override flags here: https://community.tealiumiq.com/t5/Browser-utag-js/utag-Config-Overrides/ta-p/14048
You can read more about the wait flag in the Advance Settings section of: https://community.tealiumiq.com/t5/Tealium-iQ-Tag-Management/Tags/ta-p/5016#toc-hId--1470671774
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