/SI507-HW6_torchont

Primary LanguageHTML

JavaScript assignment

Some useful resources

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

  • Tasha Torchon (torchont)

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?

// must come before a comment. //This is a comment in JavaScript.

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

<script type="text/javascript"> needs to be added near the top of the code. Here, it's on line 7.

  • 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.

console.log() is similar to print in that it facilitates the debugging process. The information in the parentheses after console.log shows up in a console, not the web browser. It allows the programmer to test the program discreetly. innerHTML is similar to print in that it can display the content or value of an element. For instance if the value of "greeting" is "Welcome back!", applying innerHTML to "greeting" will display "Welcome back!" in the web browser. innerHTML might be used in way similar to printing a variable in Python. For instance, one could change the display message by changing the element content instead of changing the element name that innerHTML refers to. innerHTML is different from print in that it can also be used to change what is displayed.

References:
https://www.w3schools.com/jsref/met_console_log.asp
https://www.w3schools.com/jsref/prop_html_innerhtml.asp

  • 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...

I would have to comment out alert("hello") on line 12.

  • 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.

Replace A name in document.querySelector('h1').innerHTML = "A name" on line 16 with my name (i.e. Tasha).

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

document represents a document object that contains the contents of the webpage.

Reference:
https://www.tutorialspoint.com/javascript/javascript_html_dom.htm

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

Here, the code is grouping the listed items into an array and finding the length of the array. The listed items include those that are ordered/numbered (e.g. the fruits near the top of the page) and those that are unordered/bulleted (e.g. the University names near the bottom).

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

It would be white.

  • 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.

The paragraph style has been defined as having a gray box with a white border. Every time the <p> tag is used, the text is displayed in such a box.

  • 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 changed the name of the function copyFunction to copyFunctionMich and created a new, similar function copyFunctionMcGill. Since copyFunction, when invoked, performed an action similar to the one I wanted, I used it as a starting point. I had initially tried to combine both processes for displaying a message after highlthing and copying University of Michigan and McGill University under the same function. When this proved unsuccessful, I created a new function instead.

  • 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>

The handleClick function displays a pop up box when invoked. The second line of code creates a Wow button that invokes the handleClick function when clicked.

  • 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.)

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?

The style, as defined in lines 7-14, is such that the error message Not valid! is displayed in red and the response for valid inputs Nice! is displayed in 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.)

var regex refers to regular expressions, which indicate what pattern a certain string should follow. Here, it is used to refer to the input given by the user. /^[a-zA-Z]+$/ indicates that the word can only include lowercase letters (a-z) and uppercase letters(A-Z). The caret at the beginning indicates that the word must start with a letter; the dollar sign at the end means that nothing can come after the string. In short, /^[a-zA-Z]+$/ means valid input is one string made up of letters.

References:
https://www.sitepoint.com/expressions-javascript/
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions

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

In JavaScript, the statement to be evaluated is in parentheses and the action to be executed is in curly brackets. In Python the statement to be evaluated is not enclosed in parentheses but is followed by a colon. The action to be executed is indented.

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

It refers to how long the message will display on the screen before fading away. Here, it will take 1,000 milliseconds.

  • 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){

This code makes it so that the if statement is executed only after some input has been submitted by the user.

References:
https://www.w3schools.com/jquery/event_ready.asp
https://www.w3schools.com/jquery/event_submit.asp

  • 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.