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JavaScript 可选链运算符
tryjsref_oper_optional_chaining
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<!DOCTYPE html> <html> <body> <h1>JavaScript Operators</h1> <h2>Optional Chaining</h2> <h2>The ?. Operator</h2> <p>The ?. operator returns undefined if an object is undefined or null (instead of throwing an error).</p> <p>Car name is:</p> <p id="demo"></p> <script> // Create an object: const car = {type:"Fiat", model:"500", color:"white"}; // Ask for car name: document.getElementById("demo").innerHTML = car?.name; </script> </body> </html>