<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<div class="container">
<div class="row mt-5">
<div class="col-lg-6">
<form id="form" action="" method="post">
<div class="form-group">
<label for="">Full Name</label>
<input type="text" name="" id="name" class="form-control" placeholder=" Full Name" onkeyup="derectedName()">
</div>
<button type="submit" class="btn btn-primary">Submit</button>
</form>
</div>
</div>
</div>
function derectedName(){
var n = $("#name").val();
var spaceCount = 0;
for(let i = 0 ; i < n.length ; i++){
if(n[i] == ' ')
spaceCount++;
if(spaceCount >= 2){
return true;
}
}
return false;
}
$("#form").submit( function(e){
var name = derectedName();
if(name != true){
alert(" يجب ان يحتوي الاسم على 3 كلمات");
e.preventDefault();
}else{
alert("submit !!");
}
});