Javascript 错误：“val.match 不是函数”
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Javascript error: "val.match is not a function"
提问by zahir
I used the match function for regular expression.
我对正则表达式使用了匹配函数。
the code I use is
我使用的代码是
if(val.match(/^s+$/) || val == "" )
but the javascript errors with
但是 javascript 错误
"val.match is not function"
I cant find what the problem is,
我找不到问题是什么，
thanks in advance
提前致谢
回答by chrisp7575
I would say that val is not a string.
我会说 val 不是字符串。
I get the "val.match is not function" error for the following
我收到以下内容的“val.match 不是函数”错误
var val=12;
if(val.match(/^s+$/) || val == ""){
document.write("success: " + val);
}
The error goes away if you explicitly convert to a string String(val)
如果您显式转换为字符串 String(val)，错误就会消失
var val=12;
if(String(val).match(/^s+$/) || val == ""){
document.write("success: " + val);
}
And if you do use a string you don't need to do the conversion
如果您确实使用字符串，则无需进行转换
var val="sss";
if(val.match(/^s+$/) || val == ""){
document.write("success: " + val);
}
回答by skipper
the problem is: val is not string
问题是：val 不是字符串
i can think of two options 1) convert to string: might be a good option if you are sure val has to be string
我可以想到两个选项 1) 转换为字符串：如果您确定 val 必须是字符串，则可能是一个不错的选择
"Same as above answer"
“与上述答案相同”
var val=12;
if(String(val).match(/^s+$/) || val == ""){
document.write("success: " + val);
}2) skip the line: in my case, it was better to just check the val type and skip if it is not string, because it was not a good idea to run "match" function anyways.
2）跳过该行：在我的情况下，最好只检查 val 类型，如果它不是字符串则跳过，因为无论如何运行“match”函数并不是一个好主意。
val = 12;
if( val.match) {
if(val.match(/^s+$/) || val == "" ) {
document.write("success: " + val);
}
} else {
document.write("not a string: " + val);
}回答by Eric Wendelin
NOTE: making this an answer as suggested above from my comment.
注意：按照我的评论中的建议，将此作为答案。
Definitely make sure val is defined and a String. Also, I'm guessing it's a typo that you don't have a slash before the 's' in your regex. If that is the case you can replace your if test with "if(val.match(/^\s*$)"
一定要确保定义了 val 并且是一个字符串。另外，我猜这是一个错字，您的正则表达式中的“s”之前没有斜线。如果是这种情况，您可以将 if 测试替换为“if(val.match(/^\s*$)”
