for Loops

A JavaScript for loop allows you to execute code a specific number of times by using a for statement that combines three statements in a single block of execution. Here’s the syntax:

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for (assignment; condition; update;){
  code to be executed;
}

The for statement uses the three statements as follows when executing the loop:

assignment: This is executed before the loop begins and not again. It is used to initialize variables that will be used in the loop as conditionals.

condition: This expression is evaluated before each iteration of the loop. If the expression evaluates to true, the loop is executed; otherwise, the for loop execution ends.

update: This is executed on each iteration, after the code in the loop has executed. This is typically used to increment a counter that is used in condition.

The following example illustrates a for loop and the nesting of one loop inside another:

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for (var x=1; x<=3; x++){
  for (var y=1; y<=3; y++){
    console.log(x + " X " + y + " = " + (x*y));
  }
}

The resulting output to the web console is:

1 X 1 = 1
1 X 2 = 2
1 X 3 = 3
2 X 1 = 2
2 X 2 = 4
2 X 3 = 6
3 X 1 = 3
3 X 2 = 6
3 X 3 = 9