function add_tag(event) {
	input_tag = event.target.closest('.tag');
	post_id = input_tag.closest('.post_container').id;
	tag_name = input_tag.children[0].value;
	fetch(url_prefix + '/add_tag', {
		method: 'POST',
		headers: {'Content-Type': 'application/json'},
		body: JSON.stringify({
			'post_id': post_id,
			'tag_name': tag_name,
		})
	}).then(function(response) {
		if(!response.ok) { throw new Error('Error adding tag!'); }
		return response.json();
	}).then(function(json) {
		if (!json.ok) { throw new Error('Could not add tag.') }
		event.target.parentElement.firstElementChild.value = '';
		let tag = document.createElement('span');
		tag.innerText = tag_name;
		tag.className = 'tag';
		let span = document.createElement('span');
		span.className = 'tag_button';
		span.addEventListener('click', remove_tag);
		span.innerText = '-';
		tag.appendChild(span);
		input_tag.closest('.tags').insertBefore(tag, input_tag);
	});
}

function remove_tag(event) {
	tag = event.target.closest('.tag');
	post_id = tag.closest('.post_container').id;
	tag_name = tag.innerText.replace(/ .*/, '');
	fetch(url_prefix + '/remove_tag', {
		method: 'POST',
		headers: {'Content-Type': 'application/json'},
		body: JSON.stringify({
			'post_id': post_id,
			'tag_name': tag_name,
		})
	}).then(function(response) {
		if(!response.ok) { throw new Error('Error removing tag!'); }
		return response.json();
	}).then(function(json) {
		if (!json.ok) { throw new Error('Could not remove tag.') }
		tag.remove();
	});
}