您可以简单地通过下面给出的一些JavaScript代码来完成此操作:

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var input = document.getElementById('logo');
var customLabel = document.getElementById('custom-file-label');

input.addEventListener('change', showFileName);

function showFileName(event) {

    var fileName = event.srcElement.files[0].name;
    console.log(fileName);
    customLabel.textContent = fileName;
}

<div class="custom-file form-group">
    <input id="logo" type="file" class="custom-file-input form-control" name="bankfile" accept="application/pdf"
        required multiple />

    <label for="logo" id="custom-file-label"></label>
</div>