<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>ГГ</title>
<style>
* {
margin:0;
padding: 0;
outline: none;
}
input[type="text"] {
width: 700px;
}
</style>
</head>
<body>
<input type="checkbox" id="check1">
<input type="checkbox" id="check2">
<input type="checkbox" id="check3">
<input type="checkbox" id="check4">
<input type="checkbox" id="check5">
<input type="checkbox" id="check6">
<input type="checkbox" id="check7">
<input type="checkbox" id="check8">
<input type="checkbox" id="check9">
<input type="checkbox" id="check10">
<input type="text" id="text">
<script>
var checkboxs = document.querySelectorAll('input[type="checkbox"]');
[].forEach.call(checkboxs, function(item){
item.onclick = function(){
document.querySelector('#text').value = "Выбранные чекбоксы: ";
for (var i = 0; i < checkboxs.length; i++){
if (checkboxs[i].checked)
document.querySelector('#text').value += checkboxs[i].id+" ";
}
}
});
</script>
</body>
</html>