[Chapter 12 Assertion]

It throws an error:

 

Uncaught #<Object>   sphere.js:6

assert                           sphere.js:6 

calculate                      sphere.js:21 

I'm trying to figure it out, searching the web, but I can't seem to figure out the solution.

[Chapter 12 Assertion]

Hello,

 I am new to the programming and javascript and I have a question. I can not figure out how to get assertion function to work. I tried it with the sphere.js that is included with the book but it does not work.

once I run the code nothing happens, but if I comment out the radius assertion it works fine.

Thanks for the help.

 

//script

function assert(expression, message) {

if (!expression) throw { name: 'Assertion Exception', message: message};

}

 

function calculate() {

'use strict';

 

// For storing the volume:

var volume;

    

    // Get a reference to the form value:

    var radius = document.getElementById('radius').value;

 

    assert((typeof radius == 'number'), 'The radius has to be a number.');

    

// Perform the calculation:

volume = (4/3) * Math.PI * Math.pow(radius, 3);

 

assert(!isNaN(volume), 'The volume is not a number');

// Format the volume:

volume = volume.toFixed(4);

 

// Display the volume:

document.getElementById('volume').value = volume;

 

// Return false to prevent submission:

return false;

    

} // End of calculate() function.

 

// Function called when the window has been loaded.

// Function needs to add an event listener to the form.

function init() {

'use strict';

document.getElementById('theForm').onsubmit = calculate;

} // End of init() function.

window.onload = init;