The page has a selection box like this:
<?php echo html::select('module', $modules, '', "class=' form-control chosen' ")?>
##There is also an input box like this:
< ?php echo html::input('title', '', "class='form-control'")?>
I want to select through JS script The box triggers an onchange() function to dynamically modify the placeholder of the input box. However, I don’t know how to write the grammar. Please help me.
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8">
</head>
<body>
<script src="http://libs.baidu.com/jquery/2.1.4/jquery.min.js"></script>
<label>请选择：</label>
<select name="source">
<option>chargeMoney1</option>
<option>chargeMoney2</option>
<option>chargeMoney3</option>
<option>chargeMoney4</option>
</select>
<br>
<label>请查看：</label><input type="text" name="target" value="" placeholder="">
<script type="text/javascript">
$('select[name=source]').on('change',function(){
// body...
var source = '';
source = $(this).val();
$('input[name=target]').attr('placeholder',source);
})
</script>
</body>
</html>
##PHP writes an interface to return the corresponding placeholder content. The front end uses ajax to call this interface and overwrite the previous placeholder with the returned content.