multi-step registration using bootstrapvalidator-prevent proceeding on error - twitter-bootstrap-3

Question

I have a multi-step reg form with each step in a fieldset,i am using bootstrap validator for validation.I made the 'next' button in first step to toggle validation.And it works well...
The problem i have is,i have to prevent going to next step on an error.
Now, validation works on clicking 'next'in first step but immediately passes to next step.
I want to stay there until validation is success...
How to do this?
i m giving my chunk of code...i have all libraries included...
...
<fieldset id="first_step">
<h2 class="fs-title">Create your account</h2>
<div class="form-group">
<label class="col-md-3 control-label">Username</label>
<div class="col-md-9">
<input type="text" class="form-control" name="uname" />
</div>
</div>
<div class="form-group">
<label class="col-md-3 control-label">Password</label>
<div class="col-md-9">
<input type="password" class="form-control" name="pwd" />
</div>
</div>
<div class="form-group">
<label class="col-md-3 control-label">Confirm Password</label>
<div class="col-md-9">
<input type="password" class="form-control" id="cpwd" />
</div>
</div>
<input type="button" name="next" id="next" class="next action-button" value="Next" />
</fieldset>
<fieldset>
<h2 class="fs-title">Personal Details</h2>
<h3 class="fs-subtitle"></h3>
<div class="form-group">
<label class="col-md-3 control-label">*Register Number</label>
<div class="col-md-9">
<input type="text" class="form-control" id="Text1" name="reg" />
</div>
</div>
<div class="form-group">
<label class="col-md-3 control-label">*Name</label>
<div class="col-md-9">
<input type="text" class="form-control" id="Text2" name="stname" />
</div>
</div>
<div class="form-group">
<label class="col-md-3 control-label"></label>
<div class="col-md-offset-3 col-md-12">
</div>
</div>
<input type="button" name="previous" class="previous action-button" value="Previous" />
<input type="submit" id="sub_but" name="submit" class="submit action-button" value="Submit" />
</fieldset>
<script type="text/javascript">
$(".next").click(function() {
$('#msform').data('bootstrapValidator').validate();
//prevent here????
//Script to slide first fielset
}
$(".previous").click(function() {
//Script to slide back to first fieldset
}
</script>