use vanila javascript syntax if others are missing.

[gcb]

if you add javaScriptEmbed in the contains group:

syntax region svelteExpression start="{" end="" contains=javaScriptEmbed,jsBlock,javascriptBlock containedin=htmlString,htmlTag,htmlArg,htmlValue,htmlH1,htmlH2,htmlH3,htmlH4,htmlH5,htmlH6,htmlHead,htmlTitle,htmlBoldItalicUnderline,htmlUnderlineBold,htmlUnderlineItalicBold,htmlUnderlineBoldItalic,htmlItalicUnderline,htmlItalicBold,htmlItalicBoldUnderline,htmlItalicUnderlineBold,htmlLink,htmlLeadingSpace,htmlBold,htmlBoldUnderline,htmlBoldItalic,htmlBoldUnderlineItalic,htmlUnderline,htmlUnderlineItalic,htmlItalic,htmlStrike,javaScript

it will work fine for people who doesn't have any of the dependencies, just the vim9 default files.

[evanleck]

Just pushed that change, let me know if that works for you. Thanks for the suggestion!