jquery - 函数内部的参数如何工作？

Question

html

<p>This is a <b>bold</b> paragraph.</p>
<button>Add</button>

jquery

$("button").click(function(){
    $("p").text(function(i,origText){
      return "Old text: " + origText + " New text: Hello world! (index: " + i + ")"; 
    });
  });

我想知道 origText 没有在函数外部调用，但它正在返回值。怎么办？

demo

Answer 1

As docs says

function(index, text)

A function returning the text content to set. Receives the index position of the element in the set and the old text value as arguments.

和How does jQuery’s .text() work, internally?