wikimedia/mediawiki-extensions-DonationInterface

( function ( $ ) {
    $( function () {
        var mc = mw.monthlyConvert, originalAmount, presetAmount;
        originalAmount = parseFloat( $( '#amount' ).val() );
        presetAmount = mc.getConvertAsk( originalAmount );
        presetAmount = ( presetAmount * 1.1 ).toFixed( 2 ); // Rounds to 2 decimal places
        presetAmount = parseFloat( presetAmount ); // Converts back to a number
        mc.presetAmount = presetAmount;
    } );
} )( jQuery );