Issue #92  (Array.indexOf(), CSS/HTML, Mobile Tools, Uncats)04/23/15

var myArray = ['one', 'two', 3, 'four', 'five'];

console.log(myArray.indexOf('two')); // 1
console.log(myArray.indexOf('four')); // 3
console.log(myArray.indexOf('six')); // -1
console.log(myArray.indexOf('3')); // -1
console.log(myArray.indexOf(3)); // 2
console.log(myArray.indexOf('one', 1)); // -1

• The search and comparison is done using strict equality. You can see this in the two examples that search for "3" and 3. Only one matches because it's a number in the array, not a string.
• Just like String.indexOf(), you can provide a second optional argument to define where to start searching. The last line in the code above can't find "one" because it starts searching at the second place in the array (1). The default, of course, is to start searching at 0.
• Remember that this method returns as soon as it finds the items being searched for, so this wouldn't be good to use if you have to find all elements, unless you utilize the second argument to allow a function to keep searching (or something else along those lines).
• Supported everywhere, including IE9, as are most other ES5 features. MDN has a polyfill.
• There's also Array.lastIndexOf(), which starts searching at the end of the array, same browser support.

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