What is the difference between an ionic and a covalent bond?

A chemical bond joins two atoms together.
In covalent bonding, atoms are joined by sharing electrons. For example, water (H₂O) is created through two OH bonds in each of which, Oxygen and Hydrogen give an electron to the electron pair.
However, in ionic bonding, electrons are donated from one atom to another. This creates electrostatic attraction between oppositely charged ions. For example, in sodium chloride (NaCl), Na can donate an electron from its outer shell to become Na⁺, and Chlorine accepts this electron to complete it's outer shell to become Cl^-. These opposite charges hold the bond together. Ionic bonding always occurs between metals and non-metals, whereas covalent bonding occurs between two non-metals.