The following program prints "Hello world" as expected
var print = function(t){
document.write(t);
};
var printAlias = print;
printAlias("Hello world");
But when I use the same technique with document.write it does not work.
var write = document.write ;
write("Something);
Can anybody tell me what am I missing?
It doesn't work because you've lost the context (the "this value") within the write method of document. You can invoke write with the call method to get it back:
write.call(document, "Something");
In your first example you are simply wrapping the call to document.write in another function, but the call itself keeps the context because you invoke write as a method of document.
So you may as well stick with the usual or your wrapper function if it's shorter code you were aiming for! Or (thanks @Esailija) you could bind the context to document at the time you create your write variable:
var write = document.write.bind(document);
var write = document.write.bind( document ) since write.call is not supported in older IE anyway
.call on DOM functions.call or .apply on DOM methods and need to support old IE. Thanks.