jQuery-在用户键入或粘贴时更改文本

Question

I'm new to jQuery and I've tried to make something but I failed so here is my problem when the user type it works but when the user paste something didn't work !!

$(document).ready(function(){

        $('#username').keyup(username_check);
});

the username_check function :

function username_check(){  
var username = $('#username').val();
if(username == "" || username.length < 4){
alert("error");
}

the field :

<input type="text" id="username" name="username" required>

Answer 1

Use .on() or .bind() to bind multiple events,

$(document).ready(function(){
   $('#username').on('keyup paste',username_check);
});


function username_check(){ 
    setTimeout( function() {
        var username = $('#username').val();
    },100);
    if(username == "" || username.length < 4){
      alert("error");
    }
}

Working Fiddle

Answer 2

如果要捕获所有input事件：

$('#username').on("input", username_check);