Get variable contents from string using javascript

Question

I want to parse javascript variable from strings. Something like that,

var string = "<script>window.arr=[1, 2.0, false]</script>";

Is there any way I can get the contents of a single variable from here?

 //something like
 function getVarContent(variable, string){
    var re = new RegExp('');
    return eval(re.exec(string))
}
getVarContent('arr', string)

Do you trust the contents of those strings? Would it be feasible to just execute it? — Marco, Nov 11 '17 at 14:38
No, I dont want to execute all of it.Simply get parts of it. — nikksan, Nov 12 '17 at 10:55

score 1 · Accepted Answer · answered Nov 11 '17 at 15:05

Maybe overkill for a simple use with a known string, but if you need to support general parsing, you can use the DOMParser if your environment supports it. (See RegEx match open tags except XHTML self-contained tags for reasons why regex may not be the answer)

[insert all the usual caveats about eval()ing strings]

var parser = new DOMParser();
var string = "<script>window.arr=[1, 2.0, false]<\/script>";
var doc = parser.parseFromString(string, "text/html");

var script = doc.querySelector('script')
eval(script.innerHTML)
console.log(window.arr)

I really dont want to execute the whole script. – nikksan Nov 12 '17 at 10:57 — nikksan, Nov 12 '17 at 10:57

score 0 · Answer 2 · answered Nov 11 '17 at 14:40

0

you should put

var string = "<script>window.arr=[1, 2.0, false]</script>";
//only valid letters
var getVar = string.match(/\[[[0-9,.a-z ]+]/g);
console.log(getVar);
var array = JSON.parse(getVar);
console.log(array);

answered Nov 11 '17 at 14:40

alessandrio

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This works the example above, but I need a general solution to be able to get specific variables. – nikksan Nov 12 '17 at 10:56

Get variable contents from string using javascript

2 Answers2