1. Testing and Comparing Values
Kevin Harville

2. If Statements
If (true) {
alert(“condition is true”); }

3. If on one line
If (something == true) alert(“It is true”);

4. If Else Statements if (condition == true) {
alert(“condition is true”); }
else {
alert(“condition is not true”);

5. Comparisons if (condition == true) == Is equal to != Is not equal to
> Is greater than
< Is less than
>= Is greater than or equal to
<= Is less than or equal to

6. Multiple Comparisons AND && If (a >= 1) && (a <= 7) {
alert(“Both conditions true”) }

7. Multiple Comparisons OR ||
Uses the “pipe” symbol, usually on the right side of the keyboard.
If (a <= 1) || (a >= 7) {
alert(“At least one condition true”) }

8. Multiple Conditions - switch
The switch statement allows the computer to choose from several paths based on the value of a given variable:
We start with the switch keyword followed by the variable to be the basis of the choice…
switch(myVariable){ }

9. Multiple Conditions - switch
We start with the switch keyword followed by the variable to be the basis of the choice…
Then we list the choices, or cases.
switch(myVariable){
case "blue":
alert("You chose Blue!");
break; }

10. Multiple Conditions - switch
switch(myVariable){
case "blue":
alert("You chose Blue!")
break;
case "red":
alert("You chose Red!") }

11. Breaking out of Switch
Break is necessary to keep subsequent lines from executing
switch(myVariable){
case "blue":
alert("You chose Blue!")
break;
case "red":
alert("You chose Red!") }

12. Use a default choice switch(myVariable){ case "blue":
alert("You chose Blue!");
break;
case "red":
alert("You chose Red!");
default:
alert("You choose something else!"); }

13. Another special feature…
To quickly assign a variable one of two values based on a condition being true:
myValue = (x==1) ? "yes" : "no"

14. Summary If If / Else Switch / Case / Break (condition) ? True : False
&& ||
== < > <= >= !=