Unknown identifier "If" (Javascript)

Hi everyone,
i’ve written a simple script in javascript to make the character respawn when he falls after the edges of the floor.
However, Mono keeps saying that there is an error: BCE0005 Unknown identifier “If”.
This is the code:

function Update () 
{
    If(transform.position.y<-100)
    {
        transform.position.y=8;
        transform.position.x=75;
        transform.position.z=12;
    }
}

Where did i go wrong?

if, not If.

You have to use “if”. Capitalization matters in almost every programming language.