what getContent() function does in jQuery?

Question

I try to get content of wp_editor() in jQuery. i am getting this error: TypeError: Cannot read property 'getContent' of null.

jQuery("#add_new").validate({
submitHandler:function() {

var course_content = encodeURIComponent(tinyMCE.get("content_id").getContent());
}
});

<div>
<form id="add_new" name="registration" action="<?php echo str_replace( '%7E', '~', $_SERVER['REQUEST_URI']); ?>" method="post" enctype="multipart/form-data">

<?php
$content = '';
$editor_id = 'content_id';
wp_editor( $content, $editor_id );
?>
<input type="submit" id="save_btn" name="save_course" class=" save_btn button button-primary" value="Save"/>
</form>
</div>

Answer 1

I think you have left # (as content_id) is an id . in 5th line of code

Like
.get("#content_id").get content().
So try with # once .