读取表单的值

function showFormValue(){
            var form = document.forms["myform"];
            alert(form.name.value);
            alert(form.xb.value);
        //debugger;断点检查
            var arr = form.ah;
            var sel = [];
            for(var i=0;i<arr.length;i++){
                if (arr[i].checked==true){
                    sel.push(arr[i].value);
                }
            }
            alert(sel.join(","));
            
            var jn = form.jn.value;
            alert(jn);
            
            var grjj = form.grjj.value;
            alert(grjj);
            
            var hid = form.hid.value;
            alert(hid);
            
            alert(document.getElementById("xm".value));
        }
        
        function setFormValue(){
            var form = document.forms["myform"];
            form.name.value = "林";
            form.jn.value = 2;
            form.grjj.value = "请输入个人简介";
            form.xb.value = 2;
            
            var ahs = form.ah;
            var len = ahs.length;
            for (var i=0;i<len;i++){
                    if(i==0){
                        continue;
                    }
                    if(i==len-1){
                        break;
                    }
                    ahs[i].checked = true;
                
            }
            
            
        }

给按钮注册一个事件

window.onload = function(){
            //获取按钮对象
            var subBtn = document.getElementById("subBtn");
            subBtn.onclick = showFormValue;
            
            setFormValue();
}