Javascript JS替换不适用于字符串
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JS replace not working on string
提问by Quadrant6
Trying to replace all instances of # in a string with a variable. It's not working but not retuning any error either.
试图用变量替换字符串中 # 的所有实例。它不起作用，但也没有重新调整任何错误。
answer_form = '<textarea name="answer_#" rows="5"></textarea>'+
'<input type="file" name="img_#" />';
question_num = 5;
answer_form.replace(/#/g, question_num);
The hashes remain.
散列仍然存在。
Not sure what I'm missing?
不确定我缺少什么？
回答by jfriend00
.replace()returns a new string (it does not modify the existing string) so you would need:
.replace()返回一个新字符串（它不会修改现有字符串），因此您需要：
answer_form = answer_form.replace(/#/g, question_num);
You probably should also make question_numa string though auto type conversions probably handle that for you.
您可能还应该创建question_num一个字符串，尽管自动类型转换可能会为您处理。
Working example: http://jsfiddle.net/jfriend00/4cAz5/
工作示例：http: //jsfiddle.net/jfriend00/4cAz5/
FYI, in Javascript, strings are immutable - an existing string is never modified. So any method which makes a modification to the string (like concat, replace, slice, substr, substring, toLowerCase, toUpperCase, etc...) ALWAYS returns a new string.
仅供参考，在 Javascript 中，字符串是不可变的——现有的字符串永远不会被修改。因此，任何对字符串进行修改的方法（如concat, replace, slice, substr, substring, toLowerCase, toUpperCase, 等...）总是返回一个新字符串。
回答by ffffff01
Your code is correct. Just add the value to the variable like this:
你的代码是正确的。只需将值添加到变量中，如下所示：
answer_form = '<textarea name="answer_#" rows="5"></textarea>'+
'<input type="file" name="img_#" />';
question_num = 5;
answer_form = answer_form.replace(/#/g, question_num);
