var str = '';
            str += '<tr style="vertical-align: middle !important;text-align: center;" id="'+hanghao+'">';
            str += '<td class="width-5 active"><input type="checkbox" value="1"/></td>';
            str += '<td class="width-15 active"><input type="text" id="fpxmIn'+hanghao+'" name="fpxm'+hanghao+'" class="form-control required" value=""  οnclick="showDiv('+hanghao+')" AUTOCOMPLETE="off"/><div id="fpxmB'+hanghao+'" style="display: none;"><div tabindex="0" οnfοcus="test()" hidefocus="true" οnblur="moveout1('+hanghao+')" style="max-height: 150px;max-width: 150px;font-size:10px;overflow: scroll;position: absolute;border:1px; solid #ccc;outline=0;" id="fpxmD'+hanghao+'"></div></div></td>';
            str += '<td class="width-15 active"><input type="text" id="bxxmIn'+hanghao+'" name="bxxm'+hanghao+'" class="form-control required" value="" οnchange="getysyeandspr('+hanghao+')" οnclick="showDiv2('+hanghao+')"   AUTOCOMPLETE="off"/><div id="bxxmB'+hanghao+'"  tabindex="0"  οnblur="moveout2('+hanghao+')" style="display: none;"><div style="max-height: 150px;max-width: 150px;font-size:10px;overflow: scroll;position: absolute;" id="bxxmD'+hanghao+'"></div></div></td>';
            str += '<td class="width-15 active"><input type="text" id="cdbmIn'+hanghao+'" name="cdbm'+hanghao+'" class="form-control required" value=""  οnchange="getysyeandspr('+hanghao+')" οnclick="showDiv3('+hanghao+')"  AUTOCOMPLETE="off"/><input type="hidden" id="cdbmidIn'+hanghao+'" name="cdbmid'+hanghao+'" /><div id="cdbmB'+hanghao+'" tabindex="0"  οnblur="moveout3('+hanghao+')" style="display: none;"><div style="max-height: 150px;max-width: 150px;font-size:10px;overflow: scroll;position: absolute;" id="cdbmD'+hanghao+'" ></div></div></td>';
            str += '<td class="width-15 active"><input type="text" id="xm'+hanghao+'" name="xm'+hanghao+'" class="form-control" value="" /><div id="xm'+hanghao+'" style="display: none;"><div style="max-height: 100px;overflow: scroll;position: absolute;" id="xm'+hanghao+'"></div></div></td>';
            str += '<td class="width-15 active"><input type="text" id="ysye'+hanghao+'" style="border-style:none" readonly=readonly  name="ysye'+hanghao+'" value="" class="form-control"/></td>';
            str += '<td class="width-15 active"><input type="text" id="je'+hanghao+'" name="je'+hanghao+'" min="0" class="form-control required"/></td>';
            str += '<td class="width-15 active"><input type="text" id="zy'+hanghao+'" name="zy'+hanghao+'" class="form-control required"/></td>';
           
            str += '</tr>';
            $("#fybxtbodyid").append(str);    

step是常量

i是变量

注意"#"+id+""   末尾还有一个""

    var id= 'step' + i;
   $("#" + id+ "").show();

   $("#" + id+ "").hide();

场景：使用vue中的v-for循环动态的添加input，在编辑的时候需要获取input的id进而获取编辑值传入后台。由于通过:id传入的id有可能空值，因此我采用了拼接的方式将属性值和下标index拼接在一起做为id，成功解决空值问题。

html代码：

<el-form-item label="姓名：">
	<div>
		<el-input v-model="dialogTable.name" placeholder="姓名" style="width:200px;"></el-input>
		<el-button @click="add">新增</el-button>
	</div>
	<div v-model="this.dialogTable.lists">
		<div v-for="(item, index) in this.dialogTable.lists" :key="index" >
			<el-input :id="nameId(item,index)" :value="item.name" style="width:200px;" @change="editNmae(item,index)"></el-input>
			<el-button @click="delete(index)">删除</el-button>
		</div>
	</div>
</el-form-item>

 js代码：

var editName = function(item,index) {
	/*var name = $('#'+item.name).val();*///此处不用这种方式获取id值，是因为id可能为特殊字符，比如逗号分号
	var id = nameId(item,index);
	var name = document.getElementById(id).value;
	this.dialogTable.lists[index].name = name;
}

var nameId = function(item,index) {
	if(item.name == null){
		return index+"name";
	}else{
		return item.name+index;
	}
}

var add = function() {	
		this.dialogTable.lists.push(
				{name:this.dialogTable.name});}
	this.dialogTable.name = undefined;
}

回头看的时候恍然大悟，大费周折实现的效果，使用vue的v-model绑定便可以实现

<el-form-item label="姓名：">
	<div>
		<el-input v-model="dialogTable.name" placeholder="姓名" style="width:200px;"></el-input>
		<el-button @click="add">新增</el-button>
	</div>
	<div v-model="this.dialogTable.lists">
		<div v-for="(item, index) in this.dialogTable.lists" :key="index" >
			<el-input v-model="item.name" style="width:200px;"></el-input>
			<el-button @click="delete(index)">删除</el-button>
		</div>
	</div>
</el-form-item>