evaluating a object string

[jman]

var x = eval("{ 'flag' : 1 }");
alert(x);
alert(x.flag);

why doesn't the above work?

 

[Henry]

            var x = eval("{ 'flag' : 1 }");
            alert(x);
            alert(x.flag);

why doesn't the above work?

Because the - eval - method treats its string input as a javascript
program and a javascript program commencing with an opening brace is a
program that starts with a block statement. That makes the content of
the block statement a syntax error.

If you want to have your string interpreted as an object literal you
have to force it into a context were it must be interpreted as an
expression. Putting parenthesis around it will achieve that end.

 

[SAM]

Henry a écrit :

Because the - eval - method treats its string input as a javascript
program and a javascript program commencing with an opening brace is a
program that starts with a block statement. That makes the content of
the block statement a syntax error.

If you want to have your string interpreted as an object literal you
have to force it into a context were it must be interpreted as an
expression. Putting parenthesis around it will achieve that end.

can you give the code ?
I didn't understand where to put these parenthesis

 

[Henry]

On Mar 6, 1:07 pm, SAM wrote:

can you give the code ?
I didn't understand where to put these parenthesis

var x = eval("({ 'flag' : 1 })");

- or:-

var x = eval("("+"{ 'flag' : 1 }"+")");

 

[SAM]

Henry a écrit :

On Mar 6, 1:07 pm, SAM wrote:


var x = eval("({ 'flag' : 1 })");

Thought having tried that ... ? !

Thanks
now it rests to understand how that works

Perhaps there is a way to see step to step how 'eval' treats the string.