Can someone please help as to why the clear button is not showing up for this input text ?

<input class="text-box single-line ui-input-text ui-body-c ui-corner-all ui-mini" id="searchInfo" name="searchInfo" type="text" value="" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" data-min="true" data-clear-btn="true">

Many Thanks

festiva_96