Why does my JavaScript code receive a "No 'Access-Control-Allow-Origin' header is present on the requested resource" error, while Postman does not?

Why does my JavaScript code receive a "No 'Access-Control-Allow-Origin' header is present on the requested resource" error, while Postman does not?

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jQuery/JavaScript: accessing contents of an iframe

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SecurityError: Blocked a frame with origin from accessing a cross-origin frame

javascript jquery security iframe same-origin-policy

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Ways to circumvent the same-origin policy

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XMLHttpRequest cannot load XXX No 'Access-Control-Allow-Origin' header

javascript cors same-origin-policy

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window.name as a data transport: a valid approach?

javascript same-origin-policy

javascript

ES6 module support in Chrome 62/Chrome Canary 64, does not work locally, CORS error

javascript google-chrome module ecmascript-6 same-origin-policy

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Using iframe with local files in Chrome

javascript google-chrome iframe same-origin-policy appjs

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Can I disable SOP (Same Origin Policy) on any browser for development?

javascript soap wsdl same-origin-policy

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WebView Javascript cross domain from a local HTML file

javascript android cross-domain android-webview same-origin-policy

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How can I sandbox untrusted user-submitted JavaScript content?

javascript iframe sandbox same-origin-policy

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Circumventing Chrome Access-control-allow-origin on the local file system?

javascript jquery google-chrome same-origin-policy

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JavaScript to detect if the parent frame is of the same origin?

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Same Origin Policy - AJAX & using Public APIs

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Same-origin policy workaround using document.domain in Javascript

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