js中常见命令

xx.html
<input id="usernameID" class="usernameCLASS" name="usernameNAME" >

xx.js
function(){
    var username= $("#usernameID").val();
    var username= $(".usernameCLASS").val();
    var username= $(‘input[name="usernameNAME"]‘).val();
}

$(function(){
    $(‘#send‘).click(function(){
         $.ajax({
             type: "get",
             url: "***/***",
             data: { username:"superslow" },
             dataType: "json",
             success: function(data){

             },
             error:function() {

             }
         });
    });
});      

$(‘ul li‘).remove();
$(‘ul li‘).each(function(){
    $(this).remove();
}); 
$("ul").find("li").remove(); 
$(‘ul‘).children().filter(‘li‘).remove();