This question already has answers here:
JavaScript object: access variable property by name as string [duplicate]
(3 answers)
Closed 8 years ago.
Please explain, why this code it's not allowed in javascript and how to make it.
var p = "inputText";
regError.p
This will give me undefined but
regError.inputText
will give me a correct result.
You can do it by using bracket notation:
regError[p]
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_Accessors
If you have an object like this
var regError = {
inputText : 'something'
}
and you want to access it with a variable, you'll have to use bracket notation
var p = "inputText";
var result = regError[p]; // returns "something"
Use with bracket notation:
regError[p]
You can check the difference between them here and there
Related
This question already has answers here:
Add a property to a JavaScript object using a variable as the name? [duplicate]
(14 answers)
Closed 7 years ago.
Is it possible to access the property of a javascript object using a string?
example: I have a javascript object "obj" that contains a property 'index'.
obj.index = 4;
Now let's say I have a string whose value is the same as a property name of my object:
var str = "index";
Can I use the value of the str variable to access the 'index' property of 'obj'?
Just use the following code:
obj[str]
You can use array Notation (squire bracket notation )
obj[str]
This question already has answers here:
JavaScript object: access variable property by name as string [duplicate]
(3 answers)
Closed 8 years ago.
I am attempting to dynamically access an object with a property value that is contained within a string. Example below:
var toolState = {
draw_point: false;
draw_line: false;
}
var dynamicText = "draw_point";
toolState.dynamicText = true; //here is the problem
I'm fairly new to JS. Sorry if this is a silly question.
Thanks
Use bracket notation instead of dot notation for variable names as properties.
toolState[dynamicText] = true;
This question already has answers here:
How to convert string as object's field name in javascript
(5 answers)
Accessing an object property with a dynamically-computed name
(19 answers)
Closed 8 years ago.
Suppose I have an object obj which has some variables in it. What I want to do is to add a new variable which has a name i gave as a parameter.
For example:
var obj=
{
number:8
}
function AddField(field_name,obj)
{
//some magical code here
}
If I call
AddField('name',obj);
i want to be able to do
obj.name='Apple'
after calling this function.
Any ideas?
Use square brackets notation:
obj[field_name] = value;
REF: http://www.jibbering.com/faq/faq_notes/square_brackets.html#vId
Use the bracket notation:
obj[field_name] = void 0;
This creates a new property with an undefined value.
If obj is already defined, you can just do obj.field_name = null or obj["field_name"] = null.
I wouldn't set any value to undefined even though the language allows for that, simply for a semantic issue: undefined means "this property/variable has not been defined" and null means "this property/variable has no value".
This question already has answers here:
Accessing an object property with a dynamically-computed name
(19 answers)
jquery dynamic id
(4 answers)
Closed 8 years ago.
i need to access
objectName.myID
but the "myID" part is dynamically generated..
how do i do this?
i tried
this['objectName.'+ variable]
i'd hate to use eval...
ps
this happens in a function (local scope) by the way..
You can access Object properties in two ways:
o.propertyname
//or
o.["propertyname"]
When using the bracket notation you have to put the propertyname in quotes or else it will be interpreted as a variable name (which in your case is exactly what you want). So in your case where you have stored the name of the property as a string, the way to go would be:
var variable = "propertyname";
o[variable];
/* /\ variable is replace with it's string representation "propertyname" */
You can even call methods this way:
var o = {};
var functionname = 'toString';
o[functionname]();
You can mix both notations, your example would look like:
var obj = 'objectName';
var prop = 'myID';
this[obj][prop]
// or this is possible too:
this.objectName[prop]
Assuming propertyName is the name of a variable holding the name of the property, for example 'myId', then you can use.
objectName[propertyName]
More details in the MDN : Working with objects
This question already has answers here:
Accessing an object property with a dynamically-computed name
(19 answers)
Closed 8 years ago.
var tinymce_toolbar = {}
tinymce_toolbar.__default =
{
script_url: '/cms/libs/js/manual/renders/tiny_mce/tiny_mce.js',
};
tinymce_toolbar.__simple =
{
script_url: '/cms/libs/js/manual/renders/tiny_mce/tiny_mce_simple.js',
};
// Doesn't work
var t = $(this).find('input[name=toolbar]').first().val();
$('.RenderHtmlEditor').tinymce(tinymce_toolbar.t);
// works
var t = $(document).find('input[name=toolbar]').first().val();
$('.RenderHtmlEditor').tinymce(tinymce_toolbar.__default);
$('.RenderHtmlEditor').tinymce(tinymce_toolbar.__simple);
how i do it to be dynamic? Thanks
object['name'] is quite same way as object.name. simply assign a associative attribute and use it as a property.
Instead of dot notation,
tinymce_toolbar.t
Use subscript notation:
tinymce_toolbar[t]