javascript - How to select different option values ​​based on the values ​​passed from the background in html select

Question

Code:

 <tr>
    <th>空间性质</th>
     <td>
         <input type="hidden" id = "class" value="{$post.post_class}"/>

         <select class="form-control" name="post[post_class]" id="class2" value="{$post.post_class}">
         <option value="0" id="op1">出售</option>
         <option value="1" id="op2">出租</option>
         </select>
         </td>
 </tr>

Display different option values ​​​​according to the value of value={$post.post_class}, value only has two values ​​​​0 and 1. TKS

Answer 1

The default selection is right, just use jquery's attr. Assuming that the default selection value is 1, the code is as follows:

$("#class option[value='1']").attr('selected',true);

Answer 2

Isn’t it enough to just set the value in the select tag to 0 or 1?

Answer 3

$("#class option[value='1']").attr('selected',true);
或
$("#class").val(1);

Answer 4

http://jsrun.net/d9YKp

Answer 5

Due to: document.querySelector('#class').valueThe value in select cannot be obtained (i.e. <select class="form-control" name="post[post_class]" id="class2" value="{$post.post_class}">).

So add a hidden input <input type="hidden" id = "class" value="{$post.post_class}"/> to get the value sent from the background, and then judge.

<script type="text/javascript">
    var sv = document.getElementById('class').value;
    if(sv == 0){
        $("#class2 option[value='0']").attr('selected',true);
    }else {
        $("#class2 option[value='1']").attr('selected',true);
    }
</script>