JS如何改变button颜色

Question

<input type="button" id="b1" value="text" onclick="this.style.color='#FF0000';">

Answer 1

document.getElementById("b1").style.color="red"

Answer 2

<script type="text/javascript">
    <!--
function changeColor(oTarget)
{
if(oTarget.style.backgroundColor=='red'){
oTarget.style.backgroundColor = 'yellow';
}else{
oTarget.style.backgroundColor = 'red';
}
    
}
    //-->
 </script>
    <input type="button" onclick="changeColor(this)" name="off" value="*0:OFF" class="bigbutton">

Answer 3

<script type="text/javascript">
    <!--
function test()
{
    document.getElementById("b1").style.color="#ff0000";
}
    //-->
 </script>
<input type="button" id="b1" value="text" onclick="test()" />