Which of these Javascript browser features work best?

Question

Typically, which of these methods of writing Javascript browser functions will work better?

Method 1

function MyFunction() 
{
    if (document.browserSpecificProperty)
       doSomethingWith(document.browserSpecificProperty);
    else
       doSomethingWith(document.someOtherProperty);
}

Method 2

var MyFunction;
if(document.browserSpecificProperty) {
    MyFunction = function() {
       doSomethingWith(document.browserSpecificProperty);
    };
} else {
    MyFunction = function() {
       doSomethingWith(document.someOtherProperty);
    };
}

Edit: Click up for all subtle answers. I fixed this function for a more correct syntax.

A few questions about the answers so far - while in most cases this is a rather pointless performance improvement, there are several reasons why you can spend some time analyzing the code:

• Slow computers, mobile devices, old browsers, etc. should work.
• Curiosity
• Use the same general operating principle to improve other scenarios in which an IF statement evaluation will take some time.

Answer 1

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Answer 2

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ECMAScript , var, . (, <script> ), eval).

Answer 3

olliej, . :

var MyFunction;
if(document.browserSpecificProperty) {
    MyFunction = function() {
       doSomethingWith(document.browserSpecificProperty);
    };
} else {
    MyFunction = function() {
       doSomethingWith(document.someOtherProperty);
    };
}

, , , , MyFunction , . ( var MyFunction; window.MyFunction = function() ... .)

Answer 4

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Answer 5

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Btw, , ?:, ( ):

var addEvent =
    document.addEventListener ? function(type, listener) {
        document.addEventListener(type, listener, false);
    } :
    document.attachEvent ? function(type, listener) {
        document.attachEvent('on' + type, listener);
    } :
    throwError;

Answer 6

: , :

var MyFunction = (function() {

      var rightProperty = document.browserSpecificProperty || document.someOtherProperty;

      return function doSomethingWith() {
            // use the rightProperty variable in your function
      }
})();

Answer 7

!

, Framework, JQuery, !

If performance is your main goal, check out SlickSpeed ! This is a page that guides the various JavaScript frames!