Now the element has both light and shadow DOM.… " with the same name in the light DOM.… It gets all nodes from the light DOM that aren’t slotted elsewhere.… </slot> – gets light children with slot="X".… It’s shown if there are no light children for the slot.
Shadow tree.A DOM element can have two types of DOM subtrees:
Light tree – a regular DOM subtree, made… All subtrees that we’ve seen in previous chapters were “light”.… But we can setup a kind of composition between shadow and light trees as well.… In particular, Shadow DOM elements may have ids that conflict with those in the light DOM.… Shadow DOM, if exists, is rendered by the browser instead of so-called “light DOM” (regular children)
Cascading.The shadow host (<custom-dialog> itself) resides in the light… Slotted elements come from light DOM, so they use document styles.… It matches elements based on two conditions:
That’s a slotted element, that comes from the light DOM… Custom CSS properties exist on all levels, both in light and shadow.… affect:
shadow tree,
shadow host with :host and :host() pseudoclasses,
slotted elements (coming from light
Retargeting does not occur if the event occurs on a slotted element, that physically lives in the light… quot;> in the example below, the event target is exactly this span element, for both shadow and light… That’s an element from the light DOM, so no retargeting.
We just need to declare the missing function.… It “fills in” the gap and adds missing implementations.… use a transpiler (if using modern syntax or operators) and polyfills (to add functions that may be missing
execution and don’t allow the visitor to interact with the rest of the page until the window has been dismissed
“a prototype”:
When we read a property from object, and it’s missing… Now if we read a property from rabbit, and it’s missing… Now if we read something from longEar, and it’s missing
If we want a “default” value to replace the missing… Please note: the prompt will run only for the missing… For potentially missing properties we can set default values using "=", like this:
focus to itself, so it causes the focus loss at the element (blur event), and when the alert is dismissed
Overlap outer variables.When in the light, can’t see anything in the darkness.… When in the darkness, can see everything in the light.
It may miss the necessary data.… It will carry additional information about the property that’s missing.
So if you run the code above and don’t dismiss the alert window for some time, then the next alert will
but it can be a more complex expression, which is only evaluated and assigned if the parameter is missing… On the other hand, it’s independently called every time when text is missing.
If i++ was missing from the example above, the loop would repeat (in theory) forever.
…will become a normal DOM as the browser reads tags and restores the missing
Everyone is happy: you, because the people don’t crowd you anymore, and fans, because they won’t miss
While reading code, a fast “vertical” eye-scan can easily miss something like counter++ and it won’t
When testing a code by manual re-runs, it’s easy to miss something.
It would be pretty bad if we complete the 1st operation, and then something goes wrong, e.g. lights out