CODEWITHSUNDEEP
jquery
user744587
user744587

Reputation:

How to define Id as variable

Let say 

 <div id = "test_id" class = "test_class"> </div>

JS 

  alert( $("#test_id").hasClass('test_class') );  // result is true

I just write another way to get the same expected result but didn't work, Why?

 var test = ' " ' + "test_id" + ' " ' ;

      alert( $(test).hasClass('test_class')  );    // not working, why ?????

Upvotes: 2

Views: 2183

Answers (6)

James Allardice
James Allardice

Reputation: 165971

Firstly, you can't assign a variable like that. The var is a keyword which signifies a variable declaration is about to occur. Get rid of the first = sign.

Secondly, you have included the " characters in your string. Those are used to declare a String literal, which is what you pass into the jQuery function in your first example. They are not part of the string itself.

Third, you didn't include the # character at the start of the selector in your second example.

If you change your second example to:

var test = '#test_id';

then it should work just fine.

Upvotes: 3

nonouco
nonouco

Reputation: 1170

  1. you forgot the "#"
  2. the ' " ' is not necessary
  3. you have two equals..

var = test = ' " ' + "test_id" + ' " ' ; //<-- this is wrong

var test = "#test_id"; // <-- this is ok

you are missing some basic skills. probably a tutorial would be useful to clear some basic things up.

Upvotes: 0

karim79
karim79

Reputation: 342635

You are double-quoting the ID stored in test:

var test = ' " ' + "test_id" + ' " ' ; // test == '"test_id"' == broken

Just do var test = "test_id", and don't forget to prepend the #

Upvotes: 0

Steve
Steve

Reputation: 50573

you forgot the #:

 var test = '#test_id';

  alert( $(test).hasClass('test_class')  );    // should be working now

Upvotes: 0

Jonathon Bolster
Jonathon Bolster

Reputation: 15961

The variable 'test' needs to be in the format of an ID selector - i.e. #test

So it should be: 

var test = '#test_id';
alert( $(test).hasClass('test_class') );

Upvotes: 1

Shef
Shef

Reputation: 45589

How about now?

var test = '#test_id'; // no need for the inner double quotes

alert( $(test).hasClass('test_class') );

Upvotes: 0

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