看起来工作没有问题。您是否记得包含相关的 Bootstrap JS 和 CSS 文件?
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<button data-target="#editMezalta" data-toggle="modal">Open Modal</button>
<div class="modal fade" id="editMezalta" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button>
<h4 class="modal-title" id="exampleModalLabel">New message</h4>
</div>
<div class="modal-body">
<form>
<div class="form-group">
<label for="recipient-name" class="control-label">Recipient:</label>
<input type="text" class="form-control" id="recipient-name">
</div>
<div class="form-group">
<label for="message-text" class="control-label">Message:</label>
<textarea class="form-control" id="message-text"></textarea>
</div>
</form>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Send message</button>
</div>
</div>
</div>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<button data-target="#editMezalta" data-toggle="modal">Open Modal</button>
<div class="modal fade" id="editMezalta" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button>
<h4 class="modal-title" id="exampleModalLabel">New message</h4>
</div>
<div class="modal-body">
<form>
<div class="form-group">
<label for="recipient-name" class="control-label">Recipient:</label>
<input type="text" class="form-control" id="recipient-name">
</div>
<div class="form-group">
<label for="message-text" class="control-label">Message:</label>
<textarea class="form-control" id="message-text"></textarea>
</div>
</form>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Send message</button>
</div>
</div>
</div>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>