Returns the first index of a substring, or -1.

• Category: JS String Reference — part of the JavaScript Tutorial on GoCareerGo
• Read the short summary above, then check the linked docs for full syntax/behaviour
• Interview tip: be ready to explain "String.prototype.indexOf()" in one sentence, then back it up with a tiny example

// String.prototype.indexOf() — minimal example
console.log("String.prototype.indexOf()");