getting the status of disabled buttons with JS

I have 7 button on a webpage. When i click on btn7, I want to check how many buttons are disabled.

<button type="submit" class="btn btn-home" name= "btn-save1" id= "btn-save1"  required="required">Save</button>
<button type="submit" class="btn btn-home" name= "btn-save2" id= "btn-save2"  required="required">Save</button>
<button type="submit" class="btn btn-home" name= "btn-save3" id= "btn-save3"  required="required">Save</button>
<button type="submit" class="btn btn-home" name= "btn-save4" id= "btn-save4"  required="required">Save</button>
<button type="submit" class="btn btn-home" name= "btn-save5" id= "btn-save5"  required="required">Save</button>
<button type="submit" class="btn btn-home" name= "btn-save6" id= "btn-save6" required="required">Save</button>

JS

<script type="text/javascript">
$('document').ready(function()
{
                $(document).on('click', '#btn-save7', function(e){
                 alert('test');
})
});
</script>

How can I check if all buttons are disabled?

Edit:

I have checked these links but these are advanced and I am not that good with jQuery. JQuery select all elements without disabled AND no readonly?

http://api.jquery.com/disabled-selector/

jQuery: Checking for disabled attribute and adding/removing it?