Getting JavaScript object key list

Question

I have a JavaScript object like

var obj = {
   key1: \'value1\',
   key2: \'value2\',
   key3: \'value3\',
   key4: \'value4\'
}

How can I

Answer 1

var obj = {
   key1: 'value1',
   key2: 'value2',
   key3: 'value3',
   key4: 'value4'
}
var keys = Object.keys(obj);
console.log('obj contains ' + keys.length + ' keys: '+  keys);

It's supported on most major browsers now.