先评论.问题是关于不使用 try/catch.
如果您不介意使用它，请阅读下面的答案.这里我们只是使用正则表达式检查一个 JSON 字符串，它适用于大多数情况，而不是所有情况.

查看 https://github 中的 450 行.com/douglascrockford/JSON-js/blob/master/json2.js

有一个检查有效 JSON 的正则表达式，例如:

if (/^[],:{}s]*$/.test(text.replace(/\["\/bfnrtu]/g, '@').替换(/"[^"\

]*"|true|false|null|-?d+(?:.d*)?(?:[eE][+-]?d+)?/g, ']').替换(/(?:^|:|,)(?:s*[)+/g, ''))) {//json没问题}别的{//json不行}

编辑:新版本的 json2.js 进行了比上面更高级的解析，但仍然基于正则表达式替换(来自 @Mrchief 的评论 )

Something like:

var jsonString = '{ "Id": 1, "Name": "Coke" }';

//should be true
IsJsonString(jsonString);

//should be false
IsJsonString("foo");
IsJsonString("<div>foo</div>")

The solution should not contain try/catch. Some of us turn on "break on all errors" and they don't like the debugger breaking on those invalid JSON strings.

A comment first. The question was about not using try/catch.
If you do not mind to use it, read the answer below. Here we just check a JSON string using a regexp, and it will work in most cases, not all cases.

Have a look around the line 450 in https://github.com/douglascrockford/JSON-js/blob/master/json2.js

There is a regexp that check for a valid JSON, something like:

if (/^[],:{}s]*$/.test(text.replace(/\["\/bfnrtu]/g, '@').
replace(/"[^"\

]*"|true|false|null|-?d+(?:.d*)?(?:[eE][+-]?d+)?/g, ']').
replace(/(?:^|:|,)(?:s*[)+/g, ''))) {

  //the json is ok

}else{

  //the json is not ok

}

EDIT: The new version of json2.js makes a more advanced parsing than above, but still based on a regexp replace ( from the comment of @Mrchief )