Crowdfunding product page

This project has a lot of things happening when choosing the rewards, so it was a good practice of JavaScript. I added lines of code to change the total backed value, number of backers, size of the progress bar, pledges left. The user can choose a default pledge value or input a value of his / her choice. Whenever the number of pledges left reaches zero, the corresponding divs become unavailable for the user to choose. One problem I had earlier on my code was when I was trying to remove the click event listener when a pledge became unavailable. At first, I was trying to invoke an anonymous function that in turn would call the function to display the correct page. Later, I couldn't remove the event listener because a new anonymous function was being created everytime I clicked on the button and because of that I could't target it for removal. I solved this issue by associating the event listener function with the .available_button and .unavailable_button classes instead of the button index. I created a function that would check which buttons were available and asign click events to them only. This function is called everytime one of the continue buttons is pressed to make sure the unavailable buttons are not clickable anymore.