JSFiddle - React, Tailwind, and code Playground

HTML

<table bgcolor="#D4D4D4" border="1" width="450" height="60">
    <tr>
        <td width="175" align="center">Land Transfer Tax Calculator</td>
    </tr>
</table>
<table border="0" bgcolor="#E7E7E7" width="450" height="69">
    <tr>
        <td height="30" align="center">Enter the Price:
            <input type="textbox" name="x1" id="price" style="width:150px">
        </td>
        <br>
    </tr>
    <tr>
        <td align="center"><font size="2">(no commas or decimals)</font>

        </td>
    </tr>
    <tr>
        <td align="center">
            <input type="checkbox" id="check1" value="">First time home buyers</td>
    </tr>
    <tr>
        <td align="center">
            <input type="button" id="calculate" style="" value="Calculate">
        </td>
    </tr>
</table>
<table bgcolor="#E7E7E7" width="450" border="0">
    <tr>
        <td align="center">Provincial Land Transfer Tax (PLTT)</td>
        <td align="center">Toronto Land Transfer Tax (TLTT)</td>
        <td align="center">Total Land Transfer Tax (PLTT + TLTT)</td>
    </tr>
    <tr>
        <td align="center">
            <input type="textbox" id="provincal" value="" style="width:135px" disabled/>
        </td>
        <td align="center">
            <input type="textbox" id="toronto" value="" style="width:135px" disabled/>
        </td>
        <td align="center">
            <input type="textbox" id="final" value="" style="width:135px" disabled>
        </td>
    </tr>
</table>

JavaScript

var calc = function()
{
   var x1 = $("#price").val();
     var y1, y2, y3, y4;
     if (x1 <= 50000) {
         y1 = x1 * 0.005; //Provinical
         y2 = x1 * 0.005; //Toronto
         y3 = y1 + y2;
     } else if (x1 <= 250000) {
         y1 = (x1 * 0.01) - 275; //Provinical
         y2 = y1; //Toronto
         y3 = y1 + y2;
     } else if (x1 <= 400000) {
         y1 = (x1 * 0.015) - 1525; //Provinical
         y2 = (x1 * 0.01) - 275; //Toronto
         y3 = y1 + y2;
     } else if (x1 >= 400001) {
         y1 = (x1 * 0.02) - 3525;
         y2 = y1 - 750;
         y3 = y1 + y2;
     }
     $("#rebate").val(y4);
     $("#final").val(y3);
     $("#toronto").val(y2);
     $("#provincal").val(y1);
};

$("#calculate").click(calc);

 $("#check1").click(function () {
     if ($("#check1").prop("checked")) {
         $("#final").val(0);
         $("#toronto").val(0);
         $("#provincal").val(0);
     }
     else{
         calc();
     }
 });