{
  "api": {
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      "__compat": {
        "mdn_url": "https://developer.mozilla.org/docs/Web/API/BeforeUnloadEvent",
        "spec_url": "https://html.spec.whatwg.org/multipage/nav-history-apis.html#the-beforeunloadevent-interface",
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          },
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          "opera": "mirror",
          "opera_android": "mirror",
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          "safari_ios": "mirror",
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          },
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          },
          "webview_ios": "mirror"
        },
        "status": {
          "experimental": false,
          "standard_track": true,
          "deprecated": false
        }
      },
      "returnValue": {
        "__compat": {
          "mdn_url": "https://developer.mozilla.org/docs/Web/API/BeforeUnloadEvent/returnValue",
          "spec_url": "https://html.spec.whatwg.org/multipage/nav-history-apis.html#dom-beforeunloadevent-returnvalue",
          "support": {
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              {
                "version_added": "119"
              },
              {
                "version_added": "30",
                "version_removed": "119",
                "partial_implementation": true,
                "notes": "Before Chrome 119, an empty string incorrectly activated the confirmation dialog."
              }
            ],
            "chrome_android": "mirror",
            "deno": {
              "version_added": false
            },
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              "version_added": "12"
            },
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              "version_added": "1.5"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": "9"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
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              "version_added": "7"
            },
            "safari_ios": "mirror",
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            },
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              "version_added": "≤37"
            },
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": true
          }
        }
      },
      "user_interaction": {
        "__compat": {
          "description": "User interaction required for dialog box",
          "support": {
            "chrome": {
              "version_added": "60"
            },
            "chrome_android": "mirror",
            "deno": {
              "version_added": false
            },
            "edge": "mirror",
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              "version_added": "44"
            },
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            "ie": {
              "version_added": false
            },
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            "opera": "mirror",
            "opera_android": "mirror",
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            },
            "safari_ios": "mirror",
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            "webview_ios": "mirror"
          },
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            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      }
    }
  }
}