Understand the idea

A condition chooses which code runs. An if statement evaluates an expression and executes its block when that expression is truthy.

Use === for strict equality when comparing values without type conversion. A single = assigns a value. A Boolean such as isOpen can be used directly as a condition. Braces keep the intended block clear even when it contains only one statement.

Read the example

This is a JavaScript fragment. Run it in a browser console or an external script. Supply any HTML or data file named in the example first.

JavaScript · EXAMPLE
const photographCount = 0;
if (photographCount === 0) {
  console.log("No photographs yet.");
} else {
  console.log("Open the gallery.");
}

A small mistake, explained

What goes wrong

Using assignment inside a condition can change a variable rather than compare it.

How to fix it. Check the operator carefully. Use === for a strict equality check and test both branches.

Try it yourself

Run the example with 0, 1 and the string "0". Explain why the string takes a different branch.

Further reading

ECMAScript — if statement

Original explanation and example prepared for HTML code FYI with AI assistance. Test the code in your own context. How these guides are made.