templates/return_book.html

{% extends "base.html" %}
{% block content %}
<h2>Return Book</h2>
<div class="card">
<form method="POST">
<label>Select Issue to Return:</label>
<select name="student_id" required onchange="this.form.book_id.value=this.options[this.selectedIndex].dataset.bookid">
{% for i in issues %}<option value="{{ i.student_id }}" data-bookid="{{ i.book_id }}">{{ i.student_id }} - {{ i.book_id }}</option>{% endfor %}
</select>
<input type="hidden" name="book_id">
<button type="submit" class="btn">Return Book</button>
<a href="{{ url_for('dashboard') }}" class="btn btn-danger">Cancel</a>
</form>
</div>
{% endblock %}