I need to auto-fill an input

Question

Good afternoon, I would like help to make a self fill

document.getElementsByClassName('nightlife_drug_quantity')[0];

I need you to always complete this with number 50.

Answer 1

Just add value="50" right into html. If you want it not to be editable just add a readonly. Or by js, like the previous comment. Example:

<input type="text" class="nightlife_drug_quantity" value="50" readonly>