切换布局
显示结果
<html> <head> <title>JavaScript String substr() Method</title> </head> <body> <script type = "text/javascript"> var str = "Apples are round, and apples are juicy."; document.write("(1,2): " + str.substr(1,2)); document.write("<br />(-2,2): " + str.substr(-2,2)); document.write("<br />(1): " + str.substr(1)); document.write("<br />(-20, 2): " + str.substr(-20,2)); document.write("<br />(20, 2): " + str.substr(20,2)); </script> </body> </html>