How can I save a score for a web game made in Unity and load it when the game starts again?

In other words, how can I load the progress for a game? I only want to store a score and load it again when the game starts (ex. if I get the 100 score and close the game, when I come back, I want to continue my progress from the 100 score)

You're looking for PlayerPrefs. Take a gander at the documentation.
• Thanks for that @DMGregory . Yes PlayerPrefs is for anything you don't care if the player goes and changes it however they please. Local highscore display? Psh, if they want to hack that no one cares. For more complex save stuff, you still have to assume that the player will find a way to rewrite the file. – Draco18s no longer trusts SE Jan 29 '16 at 21:03