What is the ruling on a wife contributing to household expenses from her salary?

A woman is permitted to work, subject to certain conditions: that the work be permissible (halal), with her husband's permission, adherence to the legal (Sharia) hijab, and avoiding mixing with men or being in seclusion with them. However, a woman's staying in her home is better for her if she is provided for by her husband or father and does not need to work. If she is permitted to work, she may assist in the household expenses, but the husband does not have the right to compel her to work or to spend [from her earnings].