The ease and ability to role the window glass up and down is because of the Toyota window regulator. This is the mechanism inside of the door panel that includes the tracks, levers, and pulleys to move the glass portion without it breaking.
The worst enemy of the Toyota window regulator is moisture. The source of moisture that penetrates this area of your Toyota is usually rain, but can also be from melting ice on the window and from the hoses used to wash your Toyota. This moisture will rust the metal components of the window regulator causing it to malfunction.
The window regulator can not be allowed to rust because any friction on its components will cause unneeded stress to be relayed to the window glass. This type of stress will eventually lead to the glass breaking.
The replacement of the window regulator is not complicated, but must be completed in the correct order. First the glass has to be placed in the upper most position and its anchor to the window regulator removed with then glass being held up by a wooden block. This way the rest of the device can be removed and replaced without damaging the glass.
Without the window glass being in the upper most position, access to the mounting bolts on the regulator will not be accessible. This bracing of the glass portion must also not be with too much stress or the glass will break further complicating this repair procedure. The seals on the door should be checked so the source of moisture can be located and fixed so your Toyota will not have to undergo this repair procedure again.