jbhammon / SI507-HW6

JavaScript assignment

Some useful resources

• Some JavaScript tutorials
• The complicated resources in the You Don't Know JS series, including your reading last week
• A resource for CSS/style/colors
• An excerpt from a specific workshop site (for a different audience than yourselves) which addresses some common questions about jQuery
• The simple JSFiddle example from class
• A W3Schools resource on JavaScript output
• Google, Piazza, your classmates, office hours, lab time!

Included files

• This README.md, which you should edit with answers to the questions
• jsPracticeLab.html, which you'll need to edit and try out
• jquerylib_submit_example.html, which you'll need to edit and try out

Your goals for this lab

Broadly

The aim for this lab is to practice adapting to and understanding code in a new-to-you (or not) language and its own libraries/packages -- JavaScript, in this case.

The programming skills you have built up till now are useful for Python programming, but, more than that, they extend to fundamentals of many kinds of programming.

This experience is not in any way about becoming an expert JavaScript programmer. Instead, it is about using what you do have experience with -- and your skills in learning new things that relate to programming -- in order to make educated judgments about some brand new-to-you code, even if you haven't learned in detail about it yet. That's part of what being in technology -- or even technology-adjacent -- will often mean.

Specifically

Below are a bunch of questions and indications of things to do. For each indication of something to do with code, there is also an accompanying question to answer or brief explanation to give.

To complete and submit this assignment, you should:

• Fork (and clone) this repository
• Add our instructional team as a collaborator to your fork (see instructions for adding collaborators on Canvas)
• Edit this README.md file with answers to the questions/prompts, briefly, using Markdown formatting so that the questions appear in bulletpoints and the answers appear clearly below each respective question, not as bulletpoints.
• Add all names of those who worked on this (as indicated below)
• Make the changes that are indicated below to each of the .html files with JavaScript programs provided. (You'll probably do this concurrently with answering questions)
• Commit (as you go) and push your changes to all three files to your GitHub forked repository.
• Submit a link to your repository on Canvas. (This HW doesn't have an autograder -- it will be graded by hand/by humans this time.)

Important notes

• You are more than welcome to work together on this, but you must each submit a repo to be graded on it, so if you do work together, you should do the following:

  • Make sure each one of you understands all the work -- YOU are responsible for using and knowing this information
  • Write each person's name & uniqname who worked on the assignment together on your submitted README.md file (you'll see a space for this below)

• In answering questions, please make sure the formatting is clear to read and that you have updated the names of everyone who worked with you, with your name first (see below).

• In answering questions, assume all of the questions include a explain briefly note -- you do NOT have to, and should not, write extended paragraphs. Be as concise as you can and explain in your own words. Don't worry about "whether it's enough" -- just worry about conveying your understanding so you can read it later, or even give it to someone else, and the answers will help/make sense.

• It is not acceptable to copy and paste answers from the internet and submit them as your own. If you cite things, make sure you provide a citation, including to links. If you get information from a resource and rephrase it so you're basically explaining an idea, that's just fine for an explanatory purpose in this assignment, but you must cite any quotes or examples that aren't yours.

• For grading: we are grading on...

  • Following the instructions
  • Approximate correctness of the code edits
  • Careful & clear answers to the questions
  • Correct answers to the questions
  • Slightly more than half the 1000 points will come from answering the questions. The rest will come from your edits to the code.

Names of people you have worked with on this assignment

• List everyone's names and uniqnames who have worked on this assignment with you, including your own name, but make sure YOUR name is first and bold
• Jackson Hammond (jbhammon)
• Jen Foran (jlforan)
• Noah Garcia (noahgarc)
• Alex Fidel (afidel)
• Joshua Cutter (jccutter)

Questions & code instructions

The first questions address the jsPracticeLab.html file.

• This is just an example question.

This is what an example answer should look like. If you want to include some code, which you probably don't have to do, you can, like this:

Some JavaScript code

• What does a code comment look like in JavaScript? What character/s do you have to put before a comment?

Comment for one line: //

Comment for multiple lines: /* */

• Explain what needs to happen to get a JavaScript program to "run", given the JavaScript you've seen in this assignment.

Given the javascript we've seen in this assignment, the file it's contained in needs to be opened in a web browser. Then the browser interprets it, and runs it line by line.

• What functions in JavaScript seem to be similar in function to the print function in Python? (There are two.) Why might you use one and not the other? Explain briefly.

alert() and console.log() both seem similar to Python's 'print' function. You might use alert() if you need to present some kind of information to a user, because it creates a popup dialog box for them. However, a developer who needs to know what a variable's value is at a certain point in their code might use console.log() to print it's value to the browsers console.

• What code would have to comment out to get rid of the pop-up box when you load the page? (Related to the last question.) Do that in the code file, and then, add code so that a text box will appear that contains the current date and time! HINT: Look through the rest of the code first...

We'd need to comment out line 12, which is alert("hello");

• How can you put your own name at the top where it currently says "A name"? Explain very briefly how to do so, and replace A name in the web page with your own name.

We can change how the 'innerHTML' is being changed on the first line of the function displayInformation(). Before it was changing the text in <h1> tags from 'A name or title goes here' to 'A name', but replacing 'A name' with 'Jackson Hammond' will display my name at the top of the page.

• What does the word document represent in this code? Explain briefly.

The word 'document' here is an object representing the HTML page the javascript is contained in. It gives us a way to for our javascript to interact with the elements and data on the page.

• What is happening in line 12 ( document.querySelector('#items').innerHTML = document.getElementsByTagName('li').length )? Explain, briefly (<= 2 sentences).

The code is counting the number of <li> elements on the page, and then setting the value of the element with the ID 'items' equal to that count.

• What color would the background of this page be if there were no JavaScript in this page?

The background would be white (#ffffff) is there was no javascript on the page.

• Why are there a couple of gray boxes on the screen with a different colored border? How could you edit this code to make them a different color? Explain briefly. Then edit the code to make those boxes some shade of blue, of your choosing.

There is a <style> tag after the <script> tag, and it defines some CSS that changes the appearance of <p> tags. Those grey boxes and borders are the result of that CSS. We could change the color from grey to blue by changing the value being given to the 'background-color' property from '#b3b3b3' to 'blue'.

• Edit the code so that, if you highlight McGill University and copy it, you see the text O Canada near the bottom of the page. Briefly explain why you made the edits that you did -- how did you know/figure out what to do?

I noticed there was a javascript function defined, called copyFunction(), that was being called when the <li> tag containing 'University of Michigan' was copied. It added the text 'Go Blue!' to the innerHTML of an element with the ID 'cheer'. I created a second function, copyFunctionCanada(), that adds 'O Canada' to the innerHTML of the same tag. Then I added a call to the new function when the <li> element for McGill University is copied.

• In the original code, when you click the button that says Wow, you see a text box! Wow. Explain briefly in your own words why the following code causes that to happen:

function handleClick(){
	alert("hello");
}

and

<button onclick=handleClick() id="wow-button">Wow</button>

We're telling the browser to run the function handleClick() when the button is clicked by the user with the code onclick=handleClick(). When that function runs it shows the user an alert with the text "hello", and that's why we see the popup when we click the "Wow" button.

• Knowing what you learned from the previous question, add code/markup to the jsPracticeLab.html file so that there is a button with the text Spring Equinox 2019 on it somewhere on the page, and when that button is clicked, a text box containing the text March 20, 2019 appears. (There's no function -- that I am aware of -- to automatically get this info, you've got to type it yourself.)

Note to self: done

The next few questions address the jquerylib_submit_example.html file.

• Check out the file jquerylib_submit_example.html. This is an example of code that uses a package called jQuery (and this will need you to have an internet connection to run it properly, although the other file does not). Check out resources above for more on jQuery!

• When you enter input that isn't valid, you see an error that is red. Why is the error in red? Why is the response for valid inputs blue?

There is javascript that runs each time the form is submitted, and it inserts different HTML into the <div> with ID 'result' if the input was valid or not. If it wasn't valid the insert <p> tag is given the class 'error', and the page's CSS says that class should have red text. Similarly, if the input is valid the <p> tag gets the class 'good', and the CSS says that text should be blue.

• What is this line var regex = /^[a-zA-Z]+$/; helping with? And if you googled something to figure that out, what did you google, and what, briefly, did you learn? (If you didn't need to google, you can leave that out, but explain briefly what that line is helping the program do, anyway.)

It helps define the filter we need to determine if the input is valid (if the input is no more than one word). It states a string should start with one or more alphabetic characters, and then nothing else after those one or more alphabetic characters.

• What's different about the syntax of conditional statements in JavaScript, compared to Python?

Javascript needs the code for each conditional to be contained in {}.

• What do you think the 10000 refers to in the code .fadeOut(10000)?

That refers to the amount of time, 10000 miliseconds, it should take to run that code.

• What do you think is going on with the following code at the beginning of the program? Note that the most important thing to do for answering this question is to be thoughtful and clear, not to be absolutely correct:

$(document).ready(function(){
    $("form").submit(function(event){

They are some functions that should be immediately invoked. That code states that when the document is 'ready' is should run the code in the first set of {}. Then when a form is submitted the chunk of code in the very next set of {} should run, which does the input validation.

• Add some code to the jquerylib_submit_example.html file so that, if the input is valid and is specifically the text hello, rather than the visible output being Nice! in blue, the visible output should be Hello to you too!, also in blue, just like Nice! is.

  • HINT: You'll have to make some changes to the conditional statement, and possibly look up some JavaScript conditional syntax. You'll also need to look carefully at what generates visible output right now.

  Note to self: done