Storage
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The Storage interface of the Web Storage API provides access to a particular domain's session or local storage. It allows, for example, the addition, modification, or deletion of stored data items.
To manipulate, for instance, the session storage for a domain, a call to Window.localStorage.
Instance properties
Storage.lengthRead only-
Returns an integer representing the number of data items stored in the
Storageobject.
Instance methods
Storage.key()-
When passed a number
n, this method will return the name of the nth key in the storage. Storage.getItem()-
When passed a key name, will return that key's value.
Storage.setItem()-
When passed a key name and value, will add that key to the storage, or update that key's value if it already exists.
Storage.removeItem()-
When passed a key name, will remove that key from the storage.
Storage.clear()-
When invoked, will empty all keys out of the storage.
Examples
Here we access a Storage object by calling localStorage. We first test whether the local storage contains data items using !localStorage.getItem('bgcolor'). If it does, we run a function called setStyles() that grabs the data items using Storage.setItem() to set the item values, then runs setStyles().
if (!localStorage.getItem("bgcolor")) {
populateStorage();
} else {
setStyles();
}
function populateStorage() {
localStorage.setItem("bgcolor", document.getElementById("bgcolor").value);
localStorage.setItem("font", document.getElementById("font").value);
localStorage.setItem("image", document.getElementById("image").value);
setStyles();
}
function setStyles() {
const currentColor = localStorage.getItem("bgcolor");
const currentFont = localStorage.getItem("font");
const currentImage = localStorage.getItem("image");
document.getElementById("bgcolor").value = currentColor;
document.getElementById("font").value = currentFont;
document.getElementById("image").value = currentImage;
htmlElem.style.backgroundColor = `#${currentColor}`;
pElem.style.fontFamily = currentFont;
imgElem.setAttribute("src", currentImage);
}
Note: To see this running as a complete working example, see our Web Storage Demo.
Specifications
| Specification |
|---|
| HTML # storage |