What is the appropriate attire for a guest to wear to an evening wedding?

* Women should not dress in all white as the bride is in white. Going to a wedding in jeans, t-shirts, running shoes are a lack of etiquette. A woman can wear a pant suit; skirt and blouse with sandals or heels; dress. The men can wear a sports jacket with good slacks, but if they can't afford it they can wear clean and pressed slacks; white shirt and tie and shined shoes.