参考代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="../js/jquery-3.3.1.min.js"></script>
<script type="text/javascript">
function setValue(obj) {
$(obj).prev().val("this is world")
}
</script>
</head>
<body>
<div id="con">
<nobr>
<input type="text" placeholder="请输入值">
<a href="#" onclick="setValue(this)">点击</a>
</nobr>
</div>
</body>
</html>