validation text box
<form class="was-validated">
<div class="row">
<div class="mb-15 col-sm-6">
<input type="text" class="form-control" placeholder="Valid state">
<div class="valid-feedback">Looks good!</div>
</div>
<div class="mb-15 col-sm-6">
<input type="text" class="form-control" placeholder="Invalid state" required="">
<div class="invalid-feedback">This is required</div>
</div>
<div class="mb-15 col-sm-6">
<textarea class="form-control" rows="2" placeholder="Valid state"></textarea>
<div class="valid-feedback">Looks good!</div>
</div>
<div class="mb-15 col-sm-6">
<textarea class="form-control" rows="2" placeholder="Invalid state"
required=""></textarea>
<div class="invalid-feedback">This is required</div>
</div>
</div>
</form>