javascript二个submit问题

<script language="JavaScript">
function chkfrm(){  
    var obj = document.forms["addForm"];
    if(obj.aabb.value == ""){
        alert("姓名不能为空!");
        obj.aabb.focus();
        return false;
    }
    return true;
    //
         
} 
 
function doSubmit1(){
    if(chkfrm()){
        document.forms["addForm"].submit();
    }else{
        return false;
    }
}
 
function doSubmit2(){
    if(chkfrm()){
        document.forms["addForm"].submit();
    }else{
        return false;
    }
}
</script>
 
 
 
 
<form id="addForm" name="addForm" method="post" action="aa.html">
<input name="aabb" type="text" />
<input name="aa" type="button" value="确定并新增" class="input_yes" onclick="doSubmit1();" />
<input name="aa" type="button" value="确定并返回" class="input_yes" onclick="doSubmit2();" />
 
</form>