javascript - 在回调函数中将 THIS 对象作为 jQuery 选择器传递

Question

我正在努力实现这样的目标:

function theMain (sel,call) {
    var el = $(sel) ;
    // Some processes etc...
    call("done") ;
}

theMain("div a",function(state){
    if (state == "done") {
        // Want "THIS" to be an DOM object,
        // But it refers WINDOW object...
        $(this).css("border","1px solid red") ;
    }
}) ;

jQuery 以某种方式做到了这一点，但是怎么做到的？

还是我必须那样做:

function theMain (sel,call) {
    var el = $(sel) ;
    // Some processes etc...
    call(el,"done") ;
}

theMain("div a",function(that,state){
    if (state == "done") {
        that.css("border","1px solid red") ;
    }
}) ;

有什么建议吗？

Answer 1

您需要使用call 来执行此操作。

参见 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/call

function theMain (sel,callback) 
{
    var $sel = $(sel);
    callback.call($sel, "done")
}

theMain("div a",function(state)
{
    if (state == "done") 
    {
      // this now refers to the jquery object (as above in $sel)
        this.css("border","1px solid red") ;
    }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<div>
<a href="#" >hello</a>
</div>