Why does jQuery not work for replacing post_content, but works for post_title?

While I am in a custom post admin ‘add post’ page, I generate a title from the check taxonomies for that post. Then I replace the post_title with the generated title, and I want to insert that title in the beginning of the post content as well.

I got it to work, except that it doesn’t insert it in the post content.

I used the same function for replacing the title and the content.

The below code works in that the title of the post is replaced, but the content is not.

I thought the jQuery would do it, but maybe the content works differently, or I used the wrong process.

Can someone help me?

Here is the HTML:

//Add CARS meta boxes

    add_action( 'add_meta_boxes' , 'car_meta_boxes' );
    function car_meta_boxes() {
        add_meta_box(
            'car_info',
            __( 'Car Info'),
            'car_info_div',
            'cars'
        );
    }
    function car_info_div( $post ) {
      // Use nonce for verification
         wp_nonce_field( plugin_basename( __FILE__ ), 'car_noncename' );

    //CARS Data Entry Fields
?>
    <div>
        <label for="car_calc_name"><?php _e("Car Name");?></label>
        <input type="text" name="car_calc_name" value="<?php echo get_post_meta($post->ID, 'car_calc_name', true);?>" /><br>
        <label for="car_calc_color"><?php _e("Car Color");?></label>
        <input type="text" name="car_calc_color" value="<?php echo get_post_meta($post->ID, 'car_calc_color', true);?>" /><br>
        <label for="car_calc_series"><?php _e("Car Series");?></label>
        <input type="text" name="car_calc_series" value="<?php echo get_post_meta($post->ID, 'car_calc_series', true);?>" /><br>
        <label for="car_calc_descript"><?php _e("Car Discription");?></label>
        <input type="text" name="car_calc_descript" value="<?php echo get_post_meta($post->ID, 'car_calc_descript', true);?>" /><br>
        <input type="button" value="Create" id="create" />
        <input type="button" value="Replace" id="replace" />
    </div>

    <script type="text/javascript">

Then the PHP:

// Cars REPLACE Button

jQuery('#replace').click(function(){
    //get the parts of the title
        var cname = jQuery('input[name="car_calc_name"]').val();
        var ccolor = jQuery('input[name="car_calc_color"]').val();
        var cseries = jQuery('input[name="car_calc_series"]').val();
        var cdescript = jQuery('input[name="car_calc_descript"]').val();

//Update title
    var title = cname + ' - ' + ccolor + ' - ' + cseries + ' - ' + cdescript;
    jQuery('input[name="post_title"]').focus().val(title);
    jQuery('input[name="post_content"]').focus().val(title);
    });
    //-->