将一个字段复制到另一个字段，但在单词之间添加逗号 - copying one field to another but adding commas between words?

copying one field to another but adding commas between words?

我有一个名为title的字段。

我有第二个字段叫做tagline。

用户将手动填写标题，我需要标签字段是标题字段的副本，但每个单词之间有逗号。

所以，用户会在标题中加入"红苹果"，然后标语将与标题相同，但单词之间有逗号。

Title = red apples
广告语= red, apples

谁能告诉我怎么做这个?

谢谢

var title = "red apples";
var tagline = title.split(" ").join(", ");

$title = 'red apples '; 
$title= trim($title); //make sure no space before or after the string, it would convert to comma
$tagline = str_replace(' ', ',', $title)

下面是一个工作示例

<input id="title" type="text" value="Red Apples" />
<input id="tagline" type="text" value="" />
<input type="button" value="do stuff" onClick="stuff()"/>
<script type="text/javascript">
    window.stuff = function(){
        title = document.getElementById("title");
        tagline = document.getElementById("tagline");
        tagline.value = title.value.split(" ").join(", ");
    }
</script>