function mouseOverOne(){
document.getElementById("b1").src="img/btn-home-3.jpg"
}
function mouseOverTwo(){
document.getElementById("b2").src="img/btn-aboutus-3.jpg"
}
function mouseOverThree(){
document.getElementById("b3").src="img/btn-services-3.jpg"
}
function mouseOverFour(){
document.getElementById("b4").src="img/btn-contact-3.jpg"
}

function mouseOutOne(){
document.getElementById("b1").src="img/btn-home-0.jpg"
}
function mouseOutTwo(){
document.getElementById("b2").src="img/btn-aboutus-0.jpg"
}
function mouseOutThree(){
document.getElementById("b3").src="img/btn-services-0.jpg"
}
function mouseOutFour(){
document.getElementById("b4").src="img/btn-contact-0.jpg"
}