function marca_1()
{
	if(document.form.chck1.checked)
	{
		document.form.b1.disabled=false
		document.form.b1.style.backgroundColor='#FFFFFF'
		document.form.b1.focus()
	}
	else
	{
		document.form.b1.disabled=true
		document.form.b1.style.backgroundColor='#D6D3CE'
		a1=document.form.b1.value
		document.form.b1.value=""
}
}


function marca_2()
{
	if(document.form.chck2.checked)
	{
		document.form.b2.disabled=false
		document.form.b2.style.backgroundColor='#FFFFFF'
		document.form.b2.focus()
	}
	else
	{
		document.form.b2.disabled=true
		document.form.b2.style.backgroundColor='#D6D3CE'
		a1=document.form.b2.value
		document.form.b2.value=""
}
}