I'm having a hard time getting my calculator to calculate and give the alert box message. Here are my instructions and what it should look like:

Can someone help me what I'm missing?

3. Code an event handler (function) named processEntries() that gets the user entries, calculates the sales tax and total, and displays those results in the text boxes. 4. Code an onload event handler that attaches the processEntries() function to the click event of the Calculate button. Then, test what you have so far. 5. Add data validation to the processEntries() function. The subtotal entry should be a valid, positive number thats less than 10,000. The tax rate should be a valid, positive number thats less than 12. The error messages should be displayed in alert dialog boxes, and the error messages should be: Subtotal must be > 0 and < 10000 Tax Rate must be > 0 and < 12 6. Add JavaScript that moves the cursor to the Subtotal field when the application starts and when the user clicks on the Calculate button. 7. Add the JavaScript event handler for the click event of the Clear button. This should clear all text boxes and move the cursor to the Subtotal field. 8. Add JavaScript event handlers for the click events of the Subtotal and Tax Rate text boxes. Each handler should clear the data from the text box.

Here is my HTML I have:

Sales Tax Calculator

Enter Subtotal and Tax Rate and click "Calculate".

Subtotal:

Tax Rate:

Sales Tax:

Total:

Here is my JS file:

var $ = function (id) { return document.getElementById(id); };

var calculate_click = function ()

{

var subtotal = parseFloat( $("subtotal").value );

var taxRate = parseFloat( $("tax_rate").value );

if(subtotal <= 0 || subtotal > 10000)

{

$("subtotal_message").innerHTML = "Must be a positive number less than $10,000";

return;

}

if(taxRate <= 0 || taxRate > 12)

{

$("tax_rate_message").innerHTML = "Must be a positive number less than 12";

return;

}

var salesTax = (subtotal * taxRate)/100;

var total = subtotal + salesTax;

$("total").value = total;

$("sales_tax").value = salesTax;

$("subtotal").focus();

}

var clear_click = function ()

{

$("subtotal").value = "";

$("tax_rate").value = "";

$("total").value = "";

$("sales_tax").value = "";

}

window.onload = function ()

{

$("subtotal").focus();

}