CODEWITHSUNDEEP
javascript
user2648537
user2648537

Reputation: 29

How to stop execution of javascript if condition is true?

I want to tag my mobile visitor with a specific URL like http://www.example.com.index.html?source=mobile i used this script to redirect visitors to the given url

<script type="text/javascript">
<!--
if (screen.width <= 800) 
{
    window.location ="http://www.example.com/index.html?source=mobile";
}

//-->
</script>

But when i used this script the page kept on loading again and again so i tried to add another condition in this script but i am confused how to make the second condition to stop loading again and again.

<script type="text/javascript">
<!--
if (screen.width >= 800) 
{
    window.location ="http://www.example.com/index.html?source=mobile";
}
 Else if (document.referrer ="http://www.example.com/index.html?source=mobile")
{
    //stop execution here
}


//-->
</script>

Now plz someone help me to stop execution of javascript if second condition is true.

Thanks in advance.

Upvotes: 2

Views: 46993

Answers (5)

access_granted
access_granted

Reputation: 1917

IE8, IE8+, IE11, Firefox, Chrome:

<script>
  ... I wana cancel here ...
  if (document.execCommand) document.execCommand('Stop');   
  if (window.stop) window.stop();   
</script>

Upvotes: 0

lededje
lededje

Reputation: 1869

Wrap the statement in an anonymous function:

(function(){
    if (screen.width >= 800)  {
        window.location = "http://www.example.com/index.html?source=mobile";
    }else if (document.referrer == "http://www.example.com/index.html?source=mobile") {
        return;
    }
});

You can only use return from within a function, despite what the other answers claim.

I am also assuming that you will be adding more code beneath the if statement, otherwise there is no use in stopping execution.

A few issues with your code:

  1. You spelt else with a capital E and is should be lowercase
  2. in the else if statement you didn't use two equals

Both issues amended in the above code

Upvotes: 2

arieljuod
arieljuod

Reputation: 15838

you should detect mobile browsers directly inside php/whateveryouuse, there's a lot of mobile detector scripts (checking the user agent how to check if the request came from mobile or computer in php)

the way it's now: the use enters the site, if the resolution is low he is redirected to... the same page! (loaded the site twice)

if you detect mobile serverside: the user enters the site only once <-- faster and works even if javascript is disabled

also, you should read something about responsive designs if you only care about the browser's resolution

Upvotes: 1

HIRA THAKUR
HIRA THAKUR

Reputation: 17757

use window.location.href to get the URL

And you have a typo:else if.. not Else if

 if (screen.width >= 800 && window.location.href !="http://www.example.com/index.html?source=mobile") 
{
    window.location.href ="http://www.example.com/index.html?source=mobile";
}

In context of stoping the execution,

else if (window.location.href ="http://www.example.com/index.html?source=mobile")
        {
            return;//to stop execution here..use return;
        }
   // This condition is unnecessary though

NOTE:There is a difference between return true,return false and return

return false: stops the event from "bubbling up".Halts the execution

return true:continues the execution.

return;

Here is a quote from the ECMA 262 standard, which JavaScript is based upon, regarding return; As noted the result is "undefined".

An ECMAScript program is considered syntactically incorrect if it contains a return statement that is not within a FunctionBody. A return statement causes a function to cease execution and return a value to the caller. If Expression is omitted, the return value is undefined. Otherwise, the return value is the value of Expression.

Upvotes: 0

Egg Vans
Egg Vans

Reputation: 944

how about

if (screen.width >= 800 && document.referrer !="http://www.example.com/index.html?source=mobile") 
{
    window.location ="http://www.example.com/index.html?source=mobile";
}

The way you have it set up now will not work as the first if will always be met, you should either do as I suggest here or put the document referer condition first (plus you need == not =).

Upvotes: 1

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