Function display

core/src/stdlib/pyscript/display.py:207–263

Display Python objects in the web page. * `*values`: Python objects to display. Each object is introspected to determine the appropriate rendering method. * `target`: DOM element ID where content should be displayed. If `None` (default), uses the current script tag's design

(*values, target=None, append=True)

def display(*values, target=None, append=True):
    """
    Display Python objects in the web page.

    * `*values`: Python objects to display. Each object is introspected to
      determine the appropriate rendering method.
    * `target`: DOM element ID where content should be displayed. If `None`
      (default), uses the current script tag's designated output area. This
      can start with '#' (which will be stripped for compatibility).
    * `append`: If `True` (default), add content to existing output. If
      `False`, replace existing content before displaying.

    When used in a worker, `display()` requires an explicit `target` parameter
    to identify where content will be displayed. If used on the main thread,
    it automatically uses the current `<script>` tag as the target. If the
    script tag has a `target` attribute, that element will be used instead.

    A ValueError is raised if a valid target cannot be found for the current
    context.

    ```python
    from pyscript import display, HTML


    # Display raw HTML.
    display(HTML("<h1>Hello, World!</h1>"))

    # Display in current script's output area.
    display("Hello, World!")

    # Display in a specific element.
    display("Hello", target="my-div")

    # Replace existing content (note the `#`).
    display("New content", target="#my-div", append=False)

    # Display multiple values in the default target.
    display("First", "Second", "Third")
    ```
    """
    if isinstance(target, str):
        # There's a valid target.
        target = target[1:] if target.startswith("#") else target
    elif is_none(target):
        target = current_target()
    element = document.getElementById(target)
    if is_none(element):
        raise ValueError(f"Cannot find element with id='{target}' in the page.")
    # If possible, use a script tag's target attribute.
    if element.tagName == "SCRIPT" and hasattr(element, "target"):
        element = element.target
    # Clear before displaying all values when not appending.
    if not append:
        element.replaceChildren()
    # Add each value.
    for value in values:
        _write_to_dom(element, value, append)