<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"><h2> prevent form submission (javascript)</h2> <div class="row"> <form name="form1" onsubmit="return someFunc()"> <input type="text" name="text1" id="text1"> <button type="submit">Submit</button> </form> </div> </div>

function someFunc() { if (1==2) { return true; } else { alert("Not submitting"); return false; } }