This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.
The Headers.keys() method returns an iterator allowing to go through all keys contained in this object. The keys are ByteString objects.
Note: This method is available in Web Workers.
Syntax
headers.keys();
Return value
Returns an iterator.
Example
// Create a test Headers object
var myHeaders = new Headers();
myHeaders.append('Content-Type', 'text/xml');
myHeaders.append('Vary', 'Accept-Language');
// Display the keys
for(var key of myHeaders.keys()) {
console.log(key);
}
The result is:
content-type vary
Specifications
| Specification | Status | Comment |
|---|---|---|
| Fetch The definition of 'Headers.keys() (as iterator<>)' in that specification. |
Living Standard | Initial definition |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | ? | 44 (44) | ? | ? | ? |
| Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | Firefox OS (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|---|
| Basic support | ? | ? | 44.0 (44) | (Yes) | ? | ? | ? |