I am new to javascript, and trying to implement a javascript function to increment today's date by 1 every time next button is pressed (would also like to include a previous button as well) and would appreciate if anyone could point me in the right direction.

I have included my work so far, a bit messy at the moment it currently displays today's date in ('yyyy-mm-dd') format and then when press the "Next" Button it will increment by one, but it will only perform this procedure once.

Code:
<script type="text/javascript">
    (function () {
        
        var date = new Date(),
            outputValue = document.getElementById( 'outputValue' ),
            dateString =  date.getFullYear().toString() + "-" + (date.getMonth() + 1) + "-" + date.getDate() ;

document.onclick = function() {
        dateString =  date.getFullYear().toString() + "-" + (date.getMonth() + 1) + "-" + (date.getDate()+1) ;
        outputValue.innerHTML = dateString;
    };
        
        outputValue.innerHTML = dateString;
         
    })();

</script>

<div id="outputValue"></div>
<input type="button" id="next" value="Next" />