
Bulma 
If your layout is implemented on the Bulma framework, the markup most likely looks like this:
html
<form>
  <div class="field">
    <label class="label">Username</label>
    <div class="control">
      <input class="input" type="text" name="name" value="">
    </div>
    <p class="help is-danger"></p>
  </div>
  <div class="field">
    <label class="label">Email</label>
    <div class="control">
      <input class="input" type="email" name="email" value="">
    </div>
    <p class="help is-danger"></p>
  </div>
  <div class="field is-grouped">
    <div class="control">
      <button type="submit" class="button is-link">Submit</button>
    </div>
    <div class="control">
      <button type="reset" class="button is-link is-light">Cancel</button>
    </div>
  </div>
</form>To prepare, you will need to do the following:
- Add 
data-error="*"attributes for elements that will be displayed with the error text. - For FormIt compatibility, placeholders with values and errors must be specified.
 - In Bulma, invalid status is specified by the 
is-dangercss class, so you need to specify it in thefetchit.frontend.input.invalid.classsystem setting. 
INFO
Markup validators still swear by the empty action attribute, so you must specify a link to the page in it.
modx
<form> 
<form action="[[~[[*id]]]]" method="post"> 
  <div class="field">
    <label class="label">Username</label>
    <div class="control">
      <input class="input" type="text" name="name" value=""> 
      <input class="input" type="text" name="name" value="[[+fi.name]]"> 
    </div>
    <p class="help is-danger"></p> 
    <p class="help is-danger" data-error="name">[[+fi.error.name]]</p> 
  </div>
  <div class="field">
    <label class="label">Email</label>
    <div class="control">
      <input class="input" type="email" name="email" value=""> 
      <input class="input" type="email" name="email" value="[[+fi.email]]"> 
    </div>
    <p class="help is-danger"></p> 
    <p class="help is-danger" data-error="email">[[+fi.error.email]]</p> 
  </div>
  <div class="field is-grouped">
    <div class="control">
      <button type="submit" class="button is-link">Submit</button>
    </div>
    <div class="control">
      <button type="reset" class="button is-link is-light">Cancel</button>
    </div>
  </div>
</form>