JavaScript Feature Reference: isPrototypeOf() Method Web Browser Support Test

Last reviewed/updated: 04 Dec 2017 | Published: 04 Dec 2017 | Status: Active
Web browser support: Internet Explorer 10+, Edge 12+, Firefox 6+, Chrome 30+, Opera 17+

1. Introduction

In this web page there are two web browser JavaScript feature support tests; 1.) a feature implementation test, and 2.) a feature capability test. First, the implementation test is run. The implementation test determines if the web browser recognizes the JavaScript isPrototypeOf() method. The implementation test is a simple test for the presence of web browser support, and a definitive test for the absence of web browser support. If the web browser does not recognize the JavaScript isPrototypeOf() method, the testing is stopped and the implementation test reports: Fail (no support): The web browser does not recognize the JavaScript isPrototypeOf() method. The web browser does not support the JavaScript isPrototypeOf() method.

If the web browser recognizes the JavaScript isPrototypeOf() method, the capability test is run. The capability test determines if the web browser's implementation of the JavaScript isPrototypeOf() method includes support for at least one isPrototypeOf() method capability. The capability test is a more definitive, albeit not an all inclusive, test for the presence of web browser support. If the web browser's implementation of the JavaScript isPrototypeOf() method includes support for the tested capability, the capability test reports: Pass (at least partial/possibly full support): The web browser recognizes the JavaScript isPrototypeOf() method, and supports at least one isPrototypeOf() method capability. The web browser at least partially/possibly fully supports the JavaScript isPrototypeOf() method. Positive determination of full web browser support is beyond the scope of this test. If the web browser's implementation of the JavaScript isPrototypeOf() method does not include support for the tested capability, the capability test reports: Pass/Fail (partial support): The web browser recognizes the JavaScript isPrototypeOf() method, but does not support at least one isPrototypeOf() method capability. The web browser partially supports the JavaScript isPrototypeOf() method.

The web browser support test source code is shown in Section 2.1. The web browser support test source code is run in Section 2.2, which shows the web browser support test result.

1.1. isPrototypeOf() Method Web Browser Support

Pass (at least partial/possibly full support): IE6+, ED12+, FF1.5+, SF3.1+, CH2+, OP7.50+.

1.2. Abbreviations

  • IE = Internet Explorer.
  • ED = Edge = EdgeHTML rendering engine (ED12+) and/or Edge browser (ED20+).
  • FF = Firefox.
  • SF = Safari.
  • CH = Chrome.
  • OP = Opera.

2. isPrototypeOf() Method Web Browser Support Test

2.1. Web Browser Support Test Source Code

<script>
if (Object.prototype.isPrototypeOf){
 var objectViaObjectConstructor = new Object(); // Instantiate instance of Object as objectViaObjectConstructor.
 function CustomConstructor(){} // CustomConstructor constructor.
 var objectViaCustomConstructor = new CustomConstructor(); // Instantiate instance of CustomConstructor as objectViaCustomConstructor.
 var objectLiteral = {}; // Instantiate instance of object literal as objectLiteral.
 if (Object.prototype.isPrototypeOf(objectViaObjectConstructor) && Object.prototype.isPrototypeOf(objectViaCustomConstructor) && CustomConstructor.prototype.isPrototypeOf(objectViaCustomConstructor) && Object.prototype.isPrototypeOf(objectLiteral)){
  document.write("<p><b>Pass</b> (at least partial/possibly full support): The web browser recognizes the JavaScript <code>isPrototypeOf()</code> method, and supports at least one <code>isPrototypeOf()</code> method capability. The web browser at least partially/possibly fully supports the JavaScript <code>isPrototypeOf()</code> method. Positive determination of full web browser support is beyond the scope of this test.</p>");
 } else {
  document.write("<p><b>Pass/Fail</b> (partial support): The web browser recognizes the JavaScript <code>isPrototypeOf()</code> method, but does not support at least one <code>isPrototypeOf()</code> method capability. The web browser partially supports the JavaScript <code>isPrototypeOf()</code> method.</p>");
 }
} else {
 document.write("<p><b>Fail</b> (no support): The web browser does not recognize the JavaScript <code>isPrototypeOf()</code> method. The web browser does not support the JavaScript <code>isPrototypeOf()</code> method.</p>");
}
</script>

2.2. Web Browser Support Test Result


3. Resources And Additional Information