jQuery.globalEval()S2C Home « Utilities « jQuery.globalEval()

Global execution scoping.

Description

The jQuery.globalEval() jQuery General utility method, allows us to execute some JavaScript code at global scope.

Shorthand version $.globalEval()

  • The jQuery.globalEval() jQuery General utility method allows scripts to be executed in the global context allowing external scripts to be loaded dynamically:
    1. What this means in practice is that the script becomes a property of the window object and is thus available in the global scope.
    2. When using the jQuery.ajax() method and having the dataType setting as script, an implicit call is made to the jQuery.globalEval() jQuery General utility method to run the script in the global scope.

Do not confuse the jQuery.globalEval() with the JavaScript eval() method. The eval() method will only 'live' in the context of the scope it was 'called' in. Outside the scope it was 'called' in the context is lost; apart from this the eval() method is deemed unsafe.

Syntax


Signature Description
jQuery.globalEval( code )Execute some JavaScript code at global scope.

Parameters


Parameter Description Type
codeThe JavaScript code to execute.String

Return

An Array object.

jQuery.globalEval( code ) Examplesgo to top of page Top

Execute some JavaScript code at global scope.

In the example below when we press left button we run the function globalEvalTest() which uses the jQuery.globalEval() jQuery General utility method to place a property on the window object. We then access this variable outside the function scope and display a message showing the variable ourMessage can be accessed globally.

When we press right button we run the function globalEvalTest2() which uses the jQuery.globalEval() jQuery General utility method to place a property on the window object. We then use $.ajax() to run an external JavaScript file url: "../../../js/test.js" . within this external script we display the variable ourMessage2 as part of a display a message showing the variable can be accessed globally.


$(function(){
  $('#btn15').one('click', function(){
    function globalEvalTest(){
      $.globalEval("var ourMessage = '*** A message ***';");
    }
    globalEvalTest();
    $('#div13').append('Can we access ourMessage globally? ' + ourMessage + '<br />');
  });
  $('#btn16').one('click', function(){
    function globalEvalTest2(){
      $.globalEval("var ourMessage2 = '*** Message 2 ***';");
    }
    globalEvalTest2();
    $.ajax({
      type: "GET",
      url: "../../../js/test.js",
      dataType: "script"
    });
  });
});

/*
 * The code for the external Javascript file called from $.ajax() (url: "../../../js/test.js")
 * is shown below.
 */
$(function(){
  var someText = 'Some text to pass across ';
  $('#div13').append('Message: ' + someText + ourMessage2 + '<br />');
});

div13. Some initial text.

Press the button below to action the above code:

            


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