源代码:
<!DOCTYPE html> <html> <body> <script> var firstname; firstname="Hege"; document.write(firstname); document.write("<br>"); firstname="Tove"; document.write(firstname); </script> <p>The script above declares a variable, assigns a value to it, displays the value, changes the value, and displays the value again.</p> </body> </html>
运行结果：