如何一次只聚焦一个按钮，而不是同时聚焦多个按钮？

<button tabindex="1">按钮1</button>
<button>按钮2</button>
<button>按钮3</button>

<button id="button1">按钮1</button>
<button id="button2">按钮2</button>
<button id="button3">按钮3</button>

<script>
    var button1 = document.getElementById('button1');
    var button2 = document.getElementById('button2');
    var button3 = document.getElementById('button3');

    button1.addEventListener('click', function() {
        button1.focus();
        button2.blur();
        button3.blur();
    });

    button2.addEventListener('click', function() {
        button1.blur();
        button2.focus();
        button3.blur();
    });

    button3.addEventListener('click', function() {
        button1.blur();
        button2.blur();
        button3.focus();
    });
</script>