javascript - How to relate values ​​to each other in js and php?

js part:
$('.new-title-info-btn').mouseenter(

<code>    function(){
        var key=$(this).attr('class').split(" ")[1];//这里key取单独给他们的class值
        $('.'+key).click(function(){
            $.ajax({ 
                url:"js4-1.php?type=findnew", 
                data:key,           //我想把变量key的值当数据发送给php,这里不知道怎么写才能把变量key的值发给php
                success:function(key){ 
                //这里我想获取到php回调的两个数据(new_title,new_class的值),然后反馈给前段修改主页面内容?
                    console.log(key);
                }, 
                error:function(e){ 
                    console.error(e); 
                } 
            });
        //console.log(key);
        })
    }
)
</code>

php:
$type=@$_GET['type'];
$sleword=@$_GET['data'];//Get the data sent by js here
switch ($type) {

<code>case findnew:
    $sql="select new_title,new_class from info_look";//这里的语句,我想把变量$sleword当作条件加到where后面即select new_title,new_class from info_look where new_calss=$sleword这样子,具体要怎么写才能在sql语句里应用变量sleword?
    $keyword=mysql_query($sql);//执行语句
    $wordArray=[];//创建空字符串承载获取到的数据
    while($row=mysql_fetch_array($keyword)){
        //$wordArray=$row;
        //这里能不能return回调$sql查询到的new_title,new_class给js,然后让js插入到指定的页面标签中去?
    }
    //print_r($wordArray);
    break;</code>

}

The questions are all written in the comments. They are newbie questions, so if there are any wrong ideas, thank you for pointing them out. If possible, I hope you can help me see how to write the method I am thinking of now, thank you

Reply content:

js part:
$('.new-title-info-btn').mouseenter(

<code>    function(){
        var key=$(this).attr('class').split(" ")[1];//这里key取单独给他们的class值
        $('.'+key).click(function(){
            $.ajax({ 
                url:"js4-1.php?type=findnew", 
                data:key,           //我想把变量key的值当数据发送给php,这里不知道怎么写才能把变量key的值发给php
                success:function(key){ 
                //这里我想获取到php回调的两个数据(new_title,new_class的值),然后反馈给前段修改主页面内容?
                    console.log(key);
                }, 
                error:function(e){ 
                    console.error(e); 
                } 
            });
        //console.log(key);
        })
    }
)
</code>

php:
$type=@$_GET['type'];
$sleword=@$_GET['data'];//Get the data sent by js here
switch ($type) {

<code>case findnew:
    $sql="select new_title,new_class from info_look";//这里的语句,我想把变量$sleword当作条件加到where后面即select new_title,new_class from info_look where new_calss=$sleword这样子,具体要怎么写才能在sql语句里应用变量sleword?
    $keyword=mysql_query($sql);//执行语句
    $wordArray=[];//创建空字符串承载获取到的数据
    while($row=mysql_fetch_array($keyword)){
        //$wordArray=$row;
        //这里能不能return回调$sql查询到的new_title,new_class给js,然后让js插入到指定的页面标签中去?
    }
    //print_r($wordArray);
    break;</code>

}

The questions are all written in the comments. It’s a newbie question, so if there are any wrong ideas, thank you for pointing them out. If possible, I hope you can help me see how to write the method I am thinking of now, thank you

$.ajax Add a field to the parameter dataType: 'json', and then use the json_encode function to make the data you want to pass to js in php into a json string echo or die and just go out .