有什么办法可以让这个 JavaScript 选项卡补全脚本更加高效吗？
此代码将集成到 AJAX 聊天系统中，以启用选项卡自动完成用户名：
var usernames = new Array();
usernames[0] = "Saladin";
usernames[1] = "Jyllaby";
usernames[2] = "CadaverKindler";
usernames[3] = "qbsuperstar03";
var text = "Text and something else q";
// Start of the script to be imported
var searchTerm = text.slice(text.lastIndexOf(" ") + 1);
var i;
for(i = 0; i < usernames.length && usernames[i].substr(0,searchTerm.length) != searchTerm; i++);
// End of the script to be imported
document.write(usernames[i]);
需要注意的几点： 用户名数组和文本变量都将通过 AJAX 从聊天本身加载（这，不幸的是，我不知道），最终的输出也将由 AJAX 处理。
有没有更有效的方法来做到这一点？
另外，关于如何处理找到的 searchTerm 的多个实例有什么提示吗？
This code is to be integrated into an AJAX Chat system to enable a tab auto-completion of user names:
var usernames = new Array();
usernames[0] = "Saladin";
usernames[1] = "Jyllaby";
usernames[2] = "CadaverKindler";
usernames[3] = "qbsuperstar03";
var text = "Text and something else q";
// Start of the script to be imported
var searchTerm = text.slice(text.lastIndexOf(" ") + 1);
var i;
for(i = 0; i < usernames.length && usernames[i].substr(0,searchTerm.length) != searchTerm; i++);
// End of the script to be imported
document.write(usernames[i]);
A couple of notes to be made: The array of usernames and the text variable would both be loaded from the chat itself via AJAX (which, unfortunately, I don't know), and the final output will be handled by AJAX as well.
Is there a more efficient way to do this?
Also, any tips on how to handle multiple instances of the searchTerm being found?
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微观优化：而不是获取子字符串并比较它（创建大量临时字符串）......
您应该使用indexOf，它不会创建临时字符串...
“searchTerm 的多个实例正在成立”？你能举一个你正在考虑的问题的例子吗？
Micro-optimization: instead of getting the substring and comparing it (creating lots of temporary strings)...
...you should use indexOf, which creates no temporary strings...
What do you mean by "multiple instances of the searchTerm being found"? Can you give an example of the problem you're thinking of?
通过保持数组排序并使用二分搜索来查找匹配项，您可以显着提高效率（如果有大量用户）。
You can make this significantly more efficient (provided large number of users) by keeping the array sorted and using binary search to find the match.
现在编码的方式是：
您正在检查用户名的长度和 searchTerm 的长度，并在每次循环时从 usernames[i] 中获取子字符串。
对于您不希望在循环过程中更改的任何这些，您应该在循环开始之前将它们存储在变量中。
从变量中获取值比检查对象属性或方法要快得多。
所以像这样：
The way you have it coded now:
You are checking the length of usernames and the length of searchTerm as well as getting a substr from usernames[i] EVERY time the loop uh, loops.
For any of these that you don't expect to change during the course of the loop, you should store them in a variable before the loop starts.
Getting a value out of a variable is much faster than checking an object property or method.
So something like: