California Code of Civil Procedure Section 906
"A fundamental principle of appellate review is that a judgment correct in law will not be reversed merely because given for the wrong reason; we review the trial court's judgment, not its reasoning." (Mayer v. C.W. Driver (2002) 98 Cal.App.4th 48, 64.)
Although a respondent who has not appealed from the judgment usually cannot raise an error on appeal (California State Employees' Assn. v. State Personnel Bd. (1986) 178 Cal.App.3d 372, 382), Code of Civil Procedure section 906 provides an exception:
"Upon an appeal pursuant to Section 904.1 or 904.2, the reviewing court may review the verdict or decision and any intermediate ruling, proceeding, order or decision which involves the merits or necessarily affects the judgment or order appealed from or which substantially affects the rights of a party, including, on any appeal from the judgment, any order on motion for a new trial, and may affirm, reverse or modify any judgment or order appealed from and may direct the proper judgment or order to be entered, and may, if necessary or proper, direct a new trial or further proceedings to be had. The respondent, or party in whose favor the judgment was given, may, without appealing from such judgment, request the reviewing court to and it may review any of the foregoing matters for the purpose of determining whether or not the appellant was prejudiced by the error or errors upon which he relies for reversal or modification of the judgment from which the appeal is taken. The provisions of this section do not authorize the reviewing court to review any decision or order from which an appeal might have been taken."
"The purpose of the statutory exception is to allow a respondent to assert a legal theory which may result in affirmance of the judgment. " (California State Employees' Assn. v. State Personnel Bd., supra, 178 Cal.App.3d at p. 382, fn. 7.)
Without having cross-appealed, a party can properly raise an argument in its capacity as a respondent that shows the trial court reached the right result, even if on the wrong theory. (Mayer v. C.W. Driver, supra, 98 Cal.App.4th at p. 57.)