what does the in in a if statmented do in javascript code example

Example 1: using if statements in javascript

if (expression) {
   Statement(s) to be executed if expression is true
} else {
   Statement(s) to be executed if expression is false
}

Example 2: javascript if statement

if (5 < 10) {
	console.log("5 is less than 10");
} else {
	console.log("5 is now bigger than 10")
}