内联JavaScript的未捕获参考错误

Question

I have the following function:

if ($(this).find('#sel').length == 0) {
    var before = $(this).text();
    var title_id = $(this).parent().attr('id');
    $(this).html("<select id='sel' onchange='selectdone(this, title_id=title_id)>
                   ...</select>");
}

From this I get Uncaught ReferenceError: title_id is not defined . Why isn't the onchange function inside on line 4 not picking up on the variable that I've defined previously? How would I rewrite the above correctly?

Answer 1

你的意思是？

$(this).html("<select id='sel' onchange='selectdone(this, "+title_id+");'>...</select>");

Answer 2

在这里使用字符串连接：

$(this).html("<select id='sel' onchange='selectdone(this, title_id=" + title_id +");'>...

Answer 3

It's happening because you're defining the "change" handler as part of a string, so the language has no idea that there's code in there.

Try this:

$(this).html($("<select/>", {
  id: 'sel',
  change: function() { selectdone(this, title_id) }
}));

Since you're using jQuery anyway, you should get in the habit of managing your event handlers via the library instead of with "onfoo" attributes.