JSFiddle - React, Tailwind, and code Playground
HTML
<TABLE align="center" width="100%" >
<TBODY>
<TR vAlign=top align=left>
<TD align="middle" width ="10%" style="padding-bottom: 1em;"><font color="black" size="2"><b>Username</b></TD>
<td width ="10%"> <input type="text" align="left" onfocus="this.style.backgroundColor='#ccc'" onblur="this.style.backgroundColor='#fff'" class="input_1000_0_0 " name="user_id" value="" size="10"/> </td> </TR>
</TBODY></TABLE>
JavaScript
$("[name='user_id']").keyup(function() {
$(this).val($(this).val().toUpperCase());
});