Q: How can i disabled partially a input? I would like to have only a part in my input disabled.
The input field is a subdomain, so i want something like this
xxxxxx.mydomain.com
Only the x must be editable, not the domain, is it possible?

A: You can use like this:
$('input').on('focus',function(){
   return $(this).val($(this).val().split('.')[0]).select(); 
});
$('input').on('change focusout',function(){
    return $(this).val($(this).val() + '.mydomain.com');
});

demo

A: You could do something like
<div class="domain">
    <input />
    <span>sometext.com</span>
</div>

then
.domain {
    display: inline-block;
    position: relative;
}
.domain input {
    padding-right: 100px;
}
.domain span {
    position: absolute;
    right: 5px;
    top: 3px;
}

Demo: Fiddle

A: Think you can use a textbox and  or , line them side by side
e.g
<div> <input type="" name="subdomain" id="subdomain"> <span id="domain">example.com</span></div>

You can then use javascript/jquery to get the domain name from the domain textbox and add it to the span, thereby making on the subdomain part editable.
Hope this helps...

A: jquery mask plugin can help.
https://plugins.jquery.com/mask/
for example:
$('#inputid').mask('aaaaaaa.exp.com');

