Here are a few title options, playing with both question format and key terms: **Direct & Specific:** * **CORS Error: \'Access-Control-Allow-Origin\' Header Missing - Why and How to Fix?** * **X

CORS Error: 'Access-Control-Allow-Origin' Header Not Present

In web applications, the Cross-Origin Resource Sharing (CORS) mechanism ensures that requests made from one domain to another are handled securely. When performing such cross-origin requests using Ajax, it's crucial to understand the importance of CORS headers to avoid errors.

XMLHttpRequest Error: 'No 'Access-Control-Allow-Origin' header is present'

This error arises when a website attempts to access resources from a different domain or subdomain without the necessary CORS headers being present. In your case, you are encountering this issue due to the custom .htaccess rewrite rules and the use of the HTML base tag.

Solution: Use 'addHeader' Instead of 'setHeader'

To resolve this issue, you should modify the code handling the CORS headers. Specifically, replace the use of the setHeader method with addHeader.

<code class="php">response.addHeader("Access-Control-Allow-Origin", "*");</code>

Implications of CORS Headers

• "*" Grants Access to all domains: The asterisk symbol allows cross-origin requests from any domain.
• Specific Domain Restriction: To restrict access to only a specific domain, replace the asterisk with the desired origin URL, such as "http://example.com".
• Read More: Consult the linked blog post for additional information on CORS and header configuration.

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