if (document.images) {
   
      
	 button1 = new Image
     button2 = new Image
	 
	 button3 = new Image
     button4 = new Image
	 
	 button5 = new Image
     button6 = new Image
	 
	 button7 = new Image
     button8 = new Image
	 
 	 button9 = new Image
     button10 = new Image
	 
	 button11 = new Image
     button12 = new Image
	 
	 button13 = new Image
     button14 = new Image
	 
	 button15 = new Image
     button16 = new Image
	 
	 button17 = new Image
     button18 = new Image
	 
	 button19 = new Image
     button20 = new Image
	 
	 button21 = new Image
     button22 = new Image
	 
	 button23 = new Image
     button24 = new Image
	 
	 button25 = new Image
     button26 = new Image
	 
	 button27 = new Image
     button28 = new Image
	 
	 button29 = new Image
     button30 = new Image
	 

     	 
	 button1.src = 'images/home.jpg'
     button2.src = 'images/home-hvr.jpg'
	 
	 button3.src = 'images/about.jpg'
     button4.src = 'images/about-hvr.jpg'
	 
	 button5.src = 'images/projects.jpg'
     button6.src = 'images/projects-hvr.jpg'
	 
	 button7.src = 'images/contact.jpg'
     button8.src = 'images/contact-hvr.jpg'
	 
	 button9.src = 'images/planning.jpg'
     button10.src = 'images/planning-hvr.jpg'
	 
	 button11.src = 'images/acoustic.jpg'
     button12.src = 'images/acoustic-hvr.jpg'
	 
	 button13.src = 'images/transport.jpg'
     button14.src = 'images/transport-hvr.jpg'
	 
	 button15.src = 'images/eia.jpg'
     button16.src = 'images/eia-hvr.jpg'
	 
	 button17.src = 'images/environmental.jpg'
     button18.src = 'images/environmental-hvr.jpg'
	 
	 button19.src = 'images/construction.jpg'
     button20.src = 'images/construction-hvr.jpg'
	 
	 button21.src = 'images/vibration.jpg'
     button22.src = 'images/vibration-hvr.jpg'
	 
	 button23.src = 'images/sound.jpg'
     button24.src = 'images/sound-hvr.jpg'
	 
	 button25.src = 'images/entertainment.jpg'
     button26.src = 'images/entertainment-hvr.jpg'
	 
	 button27.src = 'images/noise.jpg'
     button28.src = 'images/noise-hvr.jpg'
	 
	 button29.src = 'images/work.jpg'
     button30.src = 'images/work-hvr.jpg'
	 
 }


function aa()
{
document.getElementById('as1').style.display='block';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
}
function aa1(aa)
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
document.getElementById('as'+aa).style.display='block';
}

function bb()
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='block';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
}
function bb1(aa)
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
document.getElementById('as'+aa).style.display='block';
}

function cc()
{
document.getElementById('as').style.display='block';
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='block';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
}
function cc1(aa)
{
document.getElementById('as').style.display='none';
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
document.getElementById('as'+aa).style.display='block';
}

function dd()
{
document.getElementById('ass').style.display='block';
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='block';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
}
function dd1(aa)
{
document.getElementById('ass').style.display='none';
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
document.getElementById('as'+aa).style.display='block';
}

function ee()
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='block';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
}
function ee1(aa)
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
document.getElementById('as'+aa).style.display='block';
}

function ff()
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='block';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
}
function ff1(aa)
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
document.getElementById('as'+aa).style.display='block';
}

function gg()
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='block';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
}
function gg1(aa)
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
document.getElementById('as'+aa).style.display='block';
}

function hh()
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='block';
document.getElementById('as9').style.display='none';
}
function hh1(aa)
{
document.getElementById('as1').style.display='none';
document.getElementById('as2').style.display='none';
document.getElementById('as3').style.display='none';
document.getElementById('as4').style.display='none';
document.getElementById('as5').style.display='none';
document.getElementById('as6').style.display='none';
document.getElementById('as7').style.display='none';
document.getElementById('as8').style.display='none';
document.getElementById('as9').style.display='none';
document.getElementById('as'+aa).style.display='block';
}