Rounds a double-precision floating-point number toward negative infinity.
input value
rounded value
var v = floor( -4.2 ); // returns -5.0
var v = floor( 9.99999 ); // returns 9.0
var v = floor( 0.0 ); // returns 0.0
var v = floor( NaN ); // returns NaN
Rounds a double-precision floating-point number toward negative infinity.