The y property of the SVGRect interface is an alias for the DOMRect.y property. It describes the vertical coordinate of the position of the element. It reflects the SVG element's y attribute and the CSS y property.
A <coordinate> is a length in the user coordinate system that is the given distance from the origin of the user coordinate system along the relevant axis (the y-axis for Y coordinates, the x-axis for X coordinates). Its syntax is the same as that for <length>.