Executing a function passed as an argument in Javascript?

Question

I'm trying to write a generic function that will block out the UI while an AJAX call is made. What I'm trying to do is have a function A run any other function passed in as an argument. This is what I've got so far:

function blockWhileLoading(fn, msg)
{
  if (msg == null)
  {
    msg = 'Please wait while the next page is loaded...';
  }

  $.blockUI(
  {
    message: '<h1>' + msg + '</h1>',
    css:
    { 
      border: 'none', 
      padding: '15px', 
      backgroundColor: '#E3D9BA', 
      '-webkit-border-radius': '10px', 
      '-moz-border-radius': '10px', 
      color: '#4D2612'
    }
  }); 
  $('body').scrollLeft(0);

  setTimeout(function()
  {
    eval(fn);
    $.unblockUI();
  }, 1000);
}

Now when it comes time to eval the function, nothing seems to happen. Is eval not the correct way to force a function to run?

Jonathon Faust · Accepted Answer · 2010-02-12 19:26:43Z

5

No, eval is used to turn a chunk of "string" into JavaScript code at runtime. Simply call fn(). It's a function reference.

This is what eval does:

var myalert = "alert('test');";
eval(myalert);

Equivalent to:

eval("alert('test');");

answered Feb 12, 2010 at 19:26

Jonathon Faust

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Comments

wsanville · Accepted Answer · 2010-02-12 19:26:36Z

4

Just use fn();

answered Feb 12, 2010 at 19:26

wsanville

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Comments

johnmdonahue · Accepted Answer · 2010-02-12 19:28:51Z

0

If fn is being passed as an object and not a string, calling fn() should work.

answered Feb 12, 2010 at 19:28

johnmdonahue

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Comments

durron597 · Accepted Answer · 2015-08-14 23:42:22Z

0

Why not simply use:

fn();

Instead of eval.

edited Aug 14, 2015 at 23:42

durron597

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answered Feb 12, 2010 at 19:27

AnthonyWJones

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3 Comments

Sonny Boy Over a year ago

Because I'm new to Javascript and don't know any better. Hence the question.

AnthonyWJones Over a year ago

@Sonny: Sorry, the javascript looked a little advanced for someone new to javascript.

Sonny Boy Over a year ago

No worries... I'm actually inheriting a lot of this from someone else. :)

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