type="text"
class="form-control form-control-sm"
placeholder="latitude"
+ pattern="^-?\d+(\.\d+)?$"
bind:value={lat}
on:change={maybeSplitLatitude} />
</div>
type="text"
class="form-control form-control-sm"
placeholder="longitude"
+ pattern="^-?\d+(\.\d+)?$"
bind:value={lon} />
</div>
<div class="form-group">