Elements boundaries

With acrossElements option, advance-mark.js aggregates text nodes content into a single string, taking into account HTML elements. If a block element 'divides' two text nodes, and node.textContents doesn't separated by white space, the space is added to the string to separate them,
e.g. '

Header

Paragraph

' resulted: in mark.js - 'HeaderParagraph', in advance-mark.js - 'Header Paragraph'.

But the acrossElements option doesn't 'knows' any boundaries.
A blockElementsBoundary option is 'invented' to limit matches within HTML block elements.
It allows matches only across HTML inline elements (blockElementsBoundary : true).

With the blockElementsBoundary option, if a block element 'divides' two text nodes, \x01 character with spaces (it depend) is added between them, e.g. above combined string becomes 'Header \x01 Paragraph'.

If the custom tagNames are defined:

they can be the only elements that have boundaries
they can be added to the default block elements

The blockElementsBoundary option makes sense only when highlighting phrases or RegExp separate groups, or using a wildcards character * with wildcards : 'withSpaces' option.

blockElementsBoundary {boolean|object} - Option: (default is undefined)
- tagNames {string[]} - The string or array of tag name. (default is undefined)
- extend - Whether to extend the default block elements with custom elements or only specify custom elements have boundaries. (default is false)
- char - The custom boundary char. (default is \x01)

instance.mark('lorem ipsum dolor', {
    'separateWordSearch' : false,
    'acrossElements' : true,
    'blockElementsBoundary' : true,
    // or
    'blockElementsBoundary' : {
        // only these custom elements have boundaries
        'tagNames' : ['div', 'p', 'h1', 'h2'],  // optional
        // custom boundary char, default is '\x01'
        'char' : '.'   // optional
    }
});

Extending default block elements with custom elements:

context.markRegExp(/.../gi, {
    'acrossElements' : true,
    'blockElementsBoundary' : {
        // custom elements are added to the default block elements
        'tagNames' : ['tab-container', 'custom-tag'],
        'extend' : true
    }
});

The default elements are:

address, area, article, aside, audio, blockquote, body, br, button, canvas, dd, details, div, dl, dt, fieldset, figcaption, figure, footer, form, h1, h2, h3, h4, h5, h6, header, hr, iframe, img, input, label, li, main, map, menu, menuitem, meter, nav, object, ol, output, p, picture, pre, section, select, svg, table, tbody, td, textarea, tfoot, th, thead, tr, track, ul, video