As a default, the TypeScript SDK has definitions for all W3C DOM types, and for all predefined types of the target JavaScript version. However, the predefined types added may be controlled manually through the lib compiler option.
DOM manipulation may be performed with the usual properties and methods, but while paying attention to all types involved. In particular, if the strictNullChecks compiler option is true, the compiler automatically detects missing null checks. The price to pay for this verification is that the developer must provide type assertions whenever they are sure a value can't be null, and accordingly the null check is superfluous.
JavaScript libraries and frameworks, such as jQuery, may be used by providing TypeScript declaration files that describe the public types they expose. Declaration files are either included in the library packages themselves...