convert object to string

[Max]

I just wonder if there is a way of converting an object to a string.
I am using a function to send an object parameter e.g "fctng(train0);"
later on I would like to use train0 but as a string to access a
img id called <img id="train0"> .
This might be obvious to you but I am not a programmer, just trying to
learn javascript at home for fun.
Thanks

Max

[web.dev]

Hi Max,

I just wonder if there is a way of converting an object to a string.

Yes and no. It depends on the situation. Are you wanting to convert a
javascript object or a user-defined object? All javascript objects
have a toString method, however if it's an object that you've made
yourself, you'll need to provide a way to convert it to a string.

[Richard Cornford]

Max wrote:

I just wonder if there is a way of converting an object
to a string.
In loosely typed javascript any type can be converted into any other
type, and they are automatically internally converted to resolve
expressions whenever the context of use requires a different type. See:-

<URL: http://www.jibbering.com/faq/faq_not...e_convert.html >
The rule for converting Objects to strings is that the object's -
toString - method is called and the result is the string primitive value
of the object. Objects inherit default - toString - methods from their
prototype. For objects created with the object constructor, constructor
functions and object literals that - toString - function is the one
defined on the - Object.prototype -, which is not particularly useful as
it is specified as returning "[object Object]".

You get around the default - toString - methods of objects by providing
your own. EG:-

function MyObject(type, value){
this.type = type;
this.value = value;
}
MyObject.prototype.toString = function(){
return (
"[MyObject: \n\ttype = "+
this.type+
"\n\tvalue = "+
this.value+
"\n]\n"
);
};

- giving an object that when type-converted to a string (or as a result
of having its toString method called directly) will return a string
describing the object's current state. I.E.:-

var obj = new MyObject('sometype', 55);

var str = ''+obj; //concatenation forces obj's type-conversion to a
string.

alert(str); // --> outputs:-

[MyObject:
type = sometype
value = 55
]

- in the alert box.

The same result will follow from calling the object's - toString -
method directly as:-

obj.toString();
I am using a function to send an object parameter e.g
"fctng(train0);" later on I would like to use train0 but
as a string to access a img id called <img id="train0"> .
That is not a sufficient explanation of what you are attempting (or why)
to convey meaning. Remember, code always contributes to understanding
when you are talking about scripting.
This might be obvious to you but I am not a programmer,
just trying to learn javascript at home for fun.

No harm in that. Look at the information that the FAQ provides on the
subject of asking questions, it will help in the long run.

Richard.