不绑架输入--document.getElementById("linkage_"+id_type+"_echo").value="";--联动

 1 <script>
 2     function w_linkage(id_type)
 3     {
 4         var selected = $("#linkage_"+id_type+"_triger").find("option:selected").text();
 5         switch (selected)
 6         {
 7             case ‘APA‘:
 8                 document.getElementById("linkage_"+id_type+"_echo").readOnly=false;
 9                 break;
10             default :
11             case ‘AMS‘:
12                 document.getElementById("linkage_"+id_type+"_echo").value="";
13                 document.getElementById("linkage_"+id_type+"_echo").readOnly=true;
14                 break;
15         }
16     }
17 </script>

                <tr>
                    <td>位置分类： </td>
                    <td    >
                        <select class="form-control linkage_triger " name="page_position"  onclick="w_linkage(‘add‘)"  id="linkage_add_triger"  >
                            <option value="2" >APA</option>
                            <option value="1">AMS</option>
                        </select>
                    </td>
                </tr>
                <tr>
                    <td>keyword：</td>
                    <td><input type="text" name="keyword"></td>
                </tr>
                <tr>
                    <td>brand：</td>
                    <td><input type="text" name="brand"></td>
                </tr>
                <tr>
                    <td>adasin：</td>
                    <td><input type="text" name="adasin" placeholder="选AMS时，请跳过" id="linkage_add_echo"></td>
                </tr>

 1         <tr>
 2             <td>位置分类： </td>
 3             <td>
 4                 <select class="form-control" name="page_position_edit"  onclick="w_linkage(‘edit‘)"  id="linkage_edit_triger"  >
 5                     <option value="2" >APA</option>
 6                     <option value="1">AMS</option>
 7                 </select>
 8             </td>
 9         </tr>
10         <tr>
11             <td>keyword：</td>
12             <td><input type="text" name="keyword_edit" value="<?= $_GET[‘keyword‘]?>"></td>
13         </tr>
14         <tr>
15             <td>brand：</td>
16             <td><input type="text" name="brand_edit" value="<?= $_GET[‘brand‘]?>"></td>
17         </tr>
18         <tr>
19             <td>adasin：</td>
20             <td><input type="text" name="adasin_edit"  placeholder="选AMS时，请跳过"  value="<?= $_GET[‘adasin‘]?>" id="linkage_edit_echo"></td>
21         </tr>

//readyonly  交互，不绑架输入

// add edit  为同一脚本

问题：

1 document.getElementById("linkage_"+id_type+"_echo").innerHTML="";
2 document.getElementById("linkage_"+id_type+"_echo").innerText="";
3 $("#linkage_"+id_type+"_echo").emprt();;

为什么失效？