JSON string to JS object

Some modern browsers have support for parsing JSON into a native object:

var var1 = '{"cols": [{"i" ....... 66}]}';var result = JSON.parse(var1);

For the browsers that don't support it, you can download json2.js from json.org for safe parsing of a JSON object. The script will check for native JSON support and if it doesn't exist, provide the JSON global object instead. If the faster, native object is available it will just exit the script leaving it intact. You must, however, provide valid JSON or it will throw an error — you can check the validity of your JSON with http://jslint.com or http://jsonlint.com.

You can use eval(jsonString) if you trust the data in the string, otherwise you'll need to parse it properly - check json.org for some code samples.

the string in your question is not a valid json string. From json.org website:

JSON is built on two structures:

* A collection of name/value pairs. In various languages, this is   realized as an object, record, struct, dictionary, hash table, keyed list, or  associative array.* An ordered list of values. In most languages, this is realized as an  array, vector, list, or sequence.

Basically a json string will always start with either { or [.

Then as @Andy E and @Cryo said you can parse the string with json2.js or some other libraries.

IMHO you should avoid eval because it will any javascript program, so you might incur in security issues.