CODEWITHSUNDEEP
javascript
user2040597
user2040597

Reputation: 489

javascript include 2 times the same external js

I include the jquery external js file with the command:

<script type='text/javascript' src='js/jquery-1.11.0.js' ></script>

I will call it again in the same page a little bit below (this is because I am including this with php classes to make sure it is loaded before going on). So in the page, I will have 2 times the line at different places:

<script type='text/javascript' src='js/jquery-1.11.0.js' ></script>

I want to know if this will create problems in my page and if the script jquery will be loaded 2 times which would be inneficient.

Thanks,

John.

Upvotes: 2

Views: 1062

Answers (4)

NiiL
NiiL

Reputation: 2827

Depending on the library, including it more than once could have undesired effects.

Think of it like this, if you have a script that binds a click event to a button, and you include that script twice, those actions will be ran twice when the button is clicked.

You could write a simple function that you call to load a script and have it keep track of files that have already been loaded. Or, I'm sure you could probably use a pre-existing JS loader such as LabJS and modify it.

Reference: What is the danger in including the same JavaScript library twice

Upvotes: 0

basicallydan
basicallydan

Reputation: 2142

It should be fine, especially in modern browsers, but it is a little bit strange to do this.

If at any point you load jQuery plugins after the first script tag, these will no longer work because jQuery/$ has been re-initialised.

I can't think of any reason you would need to load this twice, though - are you sure you need to? Your best bet is to put the script tag at the bottom of the page, before closing the <body> tag.

Upvotes: 0

Mika Tuupola
Mika Tuupola

Reputation: 20387

It will be included twice. There is no need to do it. If you absolutely must write the include tag in two places do it second time conditionally. Code below will include jQuery only if it is not included yet.

<script>
    window.jQuery || document.write('<script src="js/jquery-1.11.0.js"><\/script>')
</script>

Upvotes: 3

Goran.it
Goran.it

Reputation: 6299

This will create issues for any plugin that is included between those two inclusion.. For example if you have :

<script type='text/javascript' src='js/jquery-1.11.0.js' ></script>
<script type='text/javascript' src='js/jquery-plugin.js' ></script>
<script type='text/javascript' src='js/jquery-1.11.0.js' ></script>

jquery-plugin.js will be overwritten and it will not work.

Upvotes: 3

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