HTML span align center not working?

A div is a block element, and will span the width of the container unless a width is set. A span is an inline element, and will have the width of the text inside it. Currently, you are trying to set align as a CSS property. Align is an attribute.

<span align="center" style="border:1px solid red;">
    This is some text in a div element!
</span>

However, the align attribute is deprecated. You should use the CSS text-align property on the container.

<div style="text-align: center;">
    <span style="border:1px solid red;">
        This is some text in a div element!
    </span>
</div>

Please use the following style. margin:auto normally used to center align the content. display:table is needed for span element

<span style="margin:auto; display:table; border:1px solid red;">
    This is some text in a div element!
</span>