changing function’s context in JavaScript
by Michał Kuklis on 31/10/2009Today I learned how to change the context of a function in JavaScript. When we do:
function test() {
this.foo = "Hello from " + this + " context.";
}
test();
alert(foo); // will show "Hello from [object Window] context.";
this.foo = "Hello from " + this + " context.";
}
test();
alert(foo); // will show "Hello from [object Window] context.";
foo will belong to the global context. In other words global object foo will be created. We can change the context to some other object by doing:
var otherContext = {};
test.call(otherContext);
alert(otherContext.foo); // will show "Hello from [object Object] context."
test.call(otherContext);
alert(otherContext.foo); // will show "Hello from [object Object] context."
In this case foo will belong to otherContext.
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