<input type="checkbox" id="new_check" onChange="noUse()" checked>
<input type="button" class="new_login_btn2" id="new_login">
<script>
var new1=document.getElementById("new_check");
var new2=document.getElementById("new_login");
function noUse(){
if(new1.checked){
new2.disabled=false;
new2.className=\'new_login_btn2\';
}
else{
new2.disabled=true;
new2.className=\'new_login_no\';
}
}
</script>