function corrigir(x) {
	x.defaultValue = ""; 
	x.style.color='#333'; 
	x.style.fontWeight='normal'; 
	x.style.outline='none';
	x.style.background='#e3f1b9';
	x.style.border='2px ridge #9c0';
}

function iniciar_corrigir() {
	var campos = document.getElementsByTagName("input");
		for (var i=0; i<campos.length-4; i++) {
		
		if (campos[i].value != "") {
		campos[i].setAttribute("onfocus", "corrigir(this)");
		}		
		
		}
}
window.onload = iniciar_corrigir;