So erscheint ein DIV, wenn er in JavaScript angeklickt wird
function showDiv() {
document.getElementById('sign-in').style.display = "block";
}
Xenophobic Xenomorph
function showDiv() {
document.getElementById('sign-in').style.display = "block";
}<a class="btn btn-default log-bar" href="#" role="button" onclick="showDiv()">Login</a>
<div id="sign-in" class="login" style="display: none;">
<form>
<div class="row">
<div class="col-md-3">
<div class="form-group inline-form">
<input type="email" class="form-control" id="email" Placeholder="email">
</div>
</div>
<div class="col-md-3">
<div class="form-group inline-form">
<input type="password" class="form-control" id="pwd">
</div>
</div>
<div class="col-md-3">
<div class="checkbox">
<label><input type="checkbox"> Remember me</label>
</div>
</div>
<div class="col-md-3">
<button type="submit" class="btn btn-default ">Submit</button>
</div>
</div>
</form>
</div>