首頁 > 開發者 > JavaScript
這篇文章主要介紹了JavaScript中的substr()方法使用詳解,是JS入門學習中的基礎知識,需要的朋友可以參考下
這個方法在一個字串返回字元開始於通過指定的字元數的指定位置。
文法
?
| 1 | string.substr(start[, length]); |
下面是參數的詳細資料：
start : 在位置開始提取字元(一個介於0和整數小於字串的長度)
length : 要用來提取的字元數
注意：如果start 是負數，substr 使用它作為從字串的末尾字元索引
傳回值:
substr方法返回基於給定參數的新的子字串
例子：
?
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | <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> |
這將產生以下結果：
?
| 1 2 3 4 5 | (1,2): pp (-2,2): Ap (1): pples are round, and apples are juicy. (-20, 2): Ap (20, 2): d |
Start building with 50+ products and up to 12 months usage for Elastic Compute Service
1 on 1 presale consultation
24/7 Technical Support 6 Free Tickets per Quarter Faster Response
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.
A comprehensive suite of global cloud computing services to power your business
Payment Methods We Support
