C

#include <lexbor/html/html.h>
#include <lexbor/core/fs.h>


#define FAILED(...)                                                            \
    do {                                                                       \
        fprintf(stderr, __VA_ARGS__);                                          \
        fprintf(stderr, "\n");                                                 \
        exit(EXIT_FAILURE);                                                    \
    }                                                                          \
    while (0)

#define PRINT(...)                                                             \
    do {                                                                       \
        fprintf(stdout, __VA_ARGS__);                                          \
        fprintf(stdout, "\n");                                                 \
    }                                                                          \
    while (0)


int
main(int argc, const char *argv[])
{
    size_t len;
    lxb_char_t *text;
    lxb_status_t status;
    lxb_dom_element_t *body, *content_root;
    lxb_html_document_t *document;
    lxb_dom_collection_t *collection;

    size_t html_len;
    const lxb_char_t *html = lexbor_fs_file_easy_read((lxb_char_t *) "/Users/alexanderborisov/new/test.html", &html_len);
    if (html == NULL) {
        return EXIT_FAILURE;
    }

    /* Initialization */
    document = lxb_html_document_create();
    if (document == NULL) {
        FAILED("Failed to create HTML Document");
    }

    /* Parse HTML */
    status = lxb_html_document_parse(document, html, html_len);
    if (status != LXB_STATUS_OK) {
        FAILED("Failed to parse HTML");
    }

    collection = lxb_dom_collection_make(&document->dom_document, 128);
    if (collection == NULL) {
        FAILED("Failed to create Collection object");
    }

    body = lxb_dom_interface_element(document->body);
    if (body == NULL) {
        FAILED("Body is NULL");
    }

    status = lxb_dom_elements_by_attr(body, collection,
                                      (lxb_char_t *) "id", 2,
                                      (lxb_char_t *) "content", 7, true);
    if (status != LXB_STATUS_OK) {
        FAILED("Failed to get elements");
    }

    if (lxb_dom_collection_length(collection) == 0) {
        FAILED("Elements not found");
    }

    content_root = lxb_dom_collection_element(collection, 0);

    text = lxb_dom_node_text_content(&content_root->node, &len);
    if (text == NULL) {
        FAILED("Failed to create text");
    }

    PRINT("%.*s", (int) len, (const char *) text);

    lxb_dom_collection_destroy(collection, true);
    lxb_html_document_destroy(document);

    return 0;
}