.append( content )
content一个元素,HTML字符串,或者jQuery对象,用来插在每个匹配元素里面的末尾。
version added: 1.4.append( function(index, html) )
function(index, html)一个返回HTML字符串的函数,该字符串用来插入到匹配元素的末尾。 Receives the index position of the element in the set and the old HTML value of the element as arguments.