function abc(kk,ll,uu)
{
	document.all.a3.value=kk;
	document.all.a2.value=ll;
	document.all.a1.value=uu;
}

<input type="button" id="a1" value="button1" onclick="abc('button1','button3','button2');">
<input type="button" id="a2" value="button1">
<input type="button" id="a3" value="button1">

function style(style)
{		
 var wh=document.getElemetntsById('div2');
var style1='
<input type="button" id="a1" value="button1" onclick="style('1')">
<input type="button" id="a2" value="button2" onclick="style('2')">
<input type="button" id="a3" value="button3" onclick="style('3')">
var style2='
<input type="button" id="a2" value="button2" onclick="style('2')">
<input type="button" id="a1" value="button1" onclick="style('1')">
<input type="button" id="a3" value="button3" onclick="style('3')">
';

style='
<input type="button" id="a3" value="button3" onclick="style('3')">
<input type="button" id="a1" value="button1" onclick="style('1')">
<input type="button" id="a2" value="button2" onclick="style('2')">
';

 
 if (style==1)
 wh.innerHTML=style1;
 if (style==2)
 wh.innerHTML=style2;
 if style==3
 wh.innerHTML=style3;
}