On keyup if value greater than X do something

Question

I have two questions, using below code:

<h2>Daily KW usage</h2>
<p>Multiply daily usage by 91, divide 91 and divide 5</p>
<input name="box11" type="text" /><br />
<input name="box21" type="hidden" value="91" />
<input name="box31" type="hidden" value="5" /><br />
<input name="box41" class="box41" type="text" />

<div class="" id="showSearchDiv" style="display:none;margin-top:10px;height:450px;background-color:red;"></div>

$('input[name="box11"]').keyup(function() {
    var box11 = $('input[name="box11"]').val();
    var box21 = $('input[name="box21"]').val();
    var box31 = $('input[name="box31"]').val();
    $('input[name="box41"]').val(box11 * box21 / box21 / box31);
});

Firstly, once the calculation is done, before entering the answer into box41 as it currently does, how do I truncate/round-down the value to two decimal places?

Secondly, when the value is calculated and placed in box41, I am trying to work out how if this value is greater than 10 to show #showSearchDiv?

I understand the basics of show/hide etc but can't seem to work out how to tie it into the one operation with keyup.

Any help or pointers would be greatly appreciated.

Answer 1

Just added a few conditions in the same method. This will your answer.

$('input[name="box11"]').keyup(function() {
    var box11 = $('input[name="box11"]').val();
    var box21 = $('input[name="box21"]').val();
    var box31 = $('input[name="box31"]').val();
    var result = box11 * box21 / box21 / box31;
    result = result.toString().match(/^-?\d+(?:\.\d{0,2})?/)[0];
    
    if(result > 10){
      $('#showSearchDiv').show();
    } else {
      $('#showSearchDiv').hide();
    }
    $('input[name="box41"]').val(result);
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<h2>Daily KW usage</h2>
<p>Multiply daily usage by 91, divide 91 and divide 5</p>
<input name="box11" type="text" /><br />
<input name="box21" type="hidden" value="91" />
<input name="box31" type="hidden" value="5" /><br />
<input name="box41" class="box41" type="text" />

<div class="" id="showSearchDiv" style="display:none;margin-top:10px;height:450px;background-color:red;"></div>