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03 - IF, LOOPS, and getElementByid

 1. The fancy name for the use of 'if statements' and the use of 'loops' are __________ and _______ respectively.

  selection / iteration

  conditionals / repeats

  ifilation / loopdum

  iteration / selection

 2. JavaScript can change the text of what is contained in an HTML paragraph (inside the p tags).

  False

  True

 3. In the following code, what is the id? 
<p id="demo">The colour selecting app</p>

  The 'p'

  the ending 'p' tag

  'demo'

  the 'colour'

 4. The following line is placed inside the script tags as it is JavaScript. Which statement best describes what it does? 
document.getElementById("demo").innerHTML = greeting;

  This will open a document and name it 'greeting'

  This is the HTML rendering of JavaScript which allows a random greeting to be displayed

  The getElementbyID command will display whatever is in the 'greeting' variable in the html text with the'demo' id

  This will place the word 'greeting' inside the paragraph tag with the 'demo' id

 5. In the following JavaScript code that uses if statements, what is missing? 
<script>
var x=prompt("Enter a number and we will do something miraculous ....")
if (x<20) 
    document.getElementById("demo").innerHTML = "Intriguing, your number is LESS than 20";

</script>

  The semi colon after the if statement. It should be if(x<20);

  Nothing is missing

  The open and closing curly braces { and } that should encase the document.getElementById command

  The full stop after the last line

 6. What is missing from this script? 
<!DOCTYPE html>
<html>
<body>

<p>Display "too young" if the age is less than 18</p>

<p id="demo">.............................</p>

<script>
var age=12;
if age < 18 {
    document.getElementById("demo").innerHTML = ">>Sorry, you are too young";
}
</script>

</body>
</html>

  The document.getElementById command should not be in the script tags but above under the first html tag

  var age=12; should be var age==12; (a double equals sign)

  Nothing is missing

  age<18 in the if statement should be encased in ordinary brackets like this: (age<18)

 7. In the following loop, which of the following statements is true? 
var i;
for (i=0; i<10;i++){
  ctx.fillRect(x,x,20,20)
  x+=21
}

  i=0 sets the starting value of variable i to 0

  All the answers stated here are correct

  The i++ is the code that tells the i variable to keep incrementing, going from 0 to 10

  In this code the loop is commanded to stop at 10, by the use of i<10;

 8. The following code, that uses a for loop, only prints out the first three vegetables in the list. What needs to be changed in order for all vegetables to be printed? 
<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Loops</h2>

<p id="demo"></p>

<script>
var veg = ["Carrots", "Tomatoes", "Turnips", "Parsnips", "Peas", "Sweet corn"];
var text = "";
var i;
for (i = 0; i < 3; i++) {
    text += veg[i] + "<br>";
}
document.getElementById("demo").innerHTML = text;
</script>

</body>
</html>

  The '3' in the for loop could be deleted and replaced with the last three vegetable names

  The i++ needs to be changed to i=all

  The '3' in the for loop could be changed to 6, or to veg.length

  The '3' in the for loop could be changed to veg.list

 9. In the following code, that uses a while loop, what should go at the end of the while loop? 
<!DOCTYPE html>
<html>
<body>

<h2>JavaScript while</h2>

<p id="demo"></p>

<script>
var text = "";
var i = 0;
while (i < 10) {
    text += "<br>The number is " + i;
    //What should go here?
}
document.getElementById("demo").innerHTML = text;
</script>

</body>
</html>

  10++

  stop =10

  i++;

  i=0

 10. In the following code, can you predict the output? 
<!DOCTYPE html>
<html>
<body>

<h1 id=demo2>JavaScript</h1>

<p id="demo1"></p>

<script>
var text = "boo";

document.getElementById("demo2").innerHTML = text;
</script>

</body>
</html>

  On execution, the content of the 'h1' html tag will say 'boo'

  On execution, the content of both the 'h1' and the 'p' tags will say 'boo'

  There will be an error, as you can only ever have one html ID

  On execution, the content of the 'p' tag will say 'boo'


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