当我单击导航栏中的按钮或其他按钮时，它会将我重定向到一个名为 undefined 的页面，但我想要做的是打开一个引导模式

Question

When I click a button in navbar or other button it redirects me to a page called undefined but what I want to do is to open a bootstrap modal

Explaining a little bit more I created a button on the page and when I put the <a> element inside the button it redirects to undefined page and I don't even have a href reference in there.

<!--button-->
<button class="au-btn au-btn-icon au-btn--blue">
    <a data-toggle="modal" data-target="#uploadModal"><i class="zmdi zmdi-plus"></i>Adicionar Item</a>
</button>

<!--Modal-->
<div class="modal fade" id="uploadModal" tabindex="-1" role="dialog" aria-labelledby="myMediulModalLabel">
    <div class="modal-dialog modal-md">
        <div style="color:white;background-color:#008CBA" class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
                <h2 style="color:white" class="modal-title" id="myModalLabel">Upload Items</h2>
            </div>
            <div class="modal-body">
                <form enctype="multipart/form-data" method="post" action="additems.php">
                <fieldset>
                    <p>Name of Item:</p>
                    <div class="form-group">
                    <input class="form-control" placeholder="Name of Item" name="item_name" type="text" required>
                    </div>
                    <p>Price:</p>
                    <div class="form-group">
                    <input id="priceinput" class="form-control" placeholder="Price" name="item_price" type="text" required>
                    </div>
                    <p>Choose Image:</p>
                    <div class="form-group">
                    <input class="form-control"  type="file" name="item_image" accept="image/*" required/>
                    </div>
                </fieldset>
            </div>
            <div class="modal-footer">
                <button class="btn btn-success btn-md" name="item_save">Save</button>
                <button type="button" class="btn btn-danger btn-md" data-dismiss="modal">Cancel</button>
            </form>
            </div>
        </div>
    </div>
</div>

Answer 1

Why do you need anchor inside button . This is the reason its not working :-

simply replace

<button class="au-btn au-btn-icon au-btn--blue">
   <a data-toggle="modal" data-target="#uploadModal"><i class="zmdi zmdi-plus"></i>Adicionar Item</a></button>

with

<button class="au-btn au-btn-icon au-btn--blue" data-toggle="modal" data-target="#uploadModal">
  <i class="zmdi zmdi-plus"></i>Adicionar Item</button>