Really? Like in "is this a valid W3C markup"? Yes (Although not recommended).
Should you use it? No. The <center> has no semantic meaning on the web page and is a styling element of par excellence. Use proper CSS alignment and positioning to style your web pages.
To align the text, use text-align: center; .
To position an element, use the fields of automatic width: margin-left: auto; margin-right: auto; margin-left: auto; margin-right: auto;
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