how to find the id of an array of elements and placing them into a var using jquery?

I have a file called text.txt that contains:

<li id="unic1">some text</li>
<li id="unic2">some text</li>

and a index.html where I try to find the id from the previous file:

<div id="div">alert(u开发者_如何学运维nic)'<div>

$(".div").load('text.txt');

$source.each(function(){
    var $unic = $("li").attr('id');
});

what am I doing wrong?

thanks edit: thanks for response.

i found that i can gram the id's like this:

var unic = $('div.hidde').find('li').map(function(i, v) { return this.id; }).get();
var unic1 = $('div.hi').find('li').map(function(i, v) { return this.id; }).get();

and i can combine them using this script:

var intersection = [];       
$(liList).each(function () {
    for (i in unic) {
    for (j in unic1) {
    if (unic[i] == unic1[j]) intersection.push(unic[i]);
}
}
});
       alert(intersection);

another questions is how to remove the

$('#result').load('text.txt', function() {
  //When load is complete
   $('.div ul').each(function(){
    var $unic = $("li").attr('id');
   });
});