Why is oxygen atom of one water molecule attracted to hydrogen atom of another water molecule?

Ionic bonds are between metals and are permanent and very strong. They could hardly be called an attraction. This happens when one atom steals another atoms electron. Covalent bonds are strong but occurs between two different atoms they are also permanent to in this bond they share electrons and not take away. Hydrogen bonds are temporary and occur between molecules that have hydrogen and molecules that have elements like oxygen which become attracted to the hydrogen. These are weak but when they build up they can become very strong.