it should work
$( "input[type=submit]" ).button({icons: {primary: "ui-icon-circle-plus"}}) .click(function( event ) { event.preventDefault(); });
or you will install it later:
$( "input[type=submit]" ).button( "option", "icons", { primary: "ui-icon-circle-plus", secondary: "<your_second_icon>" } );
Here is a working example.
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