Prototype tool function learning

$H is a convenient way to create a Hash object. For specific references to Hash objects [Prototype Learning - Hash Objects]
$R is a convenient method for resume ObjectRange objects. For specific references to ObjectRange objects [Prototype Learning - ObjectRange Object]
:
Accepts an arbitrary number of functions and returns the result of the first one that doesn't throw an error.

Copy the codeThe code is as follows:

//It is to use a loop to nest try...catch to complete this tool function
var Try = { 
these: function() { 
var returnValue; 
for (var i = 0, length = ; i < length; i++) { 
var lambda = arguments[i]; 
try { 
returnValue = lambda(); 
break; 
} catch (e) { } 
} 
return returnValue; 
} 
};

See an example (different browsers have different methods to create XMLHttpRequest):

Copy the codeThe code is as follows:

getTransport: function() { 
return ( 
function() { return new XMLHttpRequest() }, 
function() { return new ActiveXObject('') }, 
function() { return new ActiveXObject('') 
} ) || false; }

()：
Based on the name of this method, you can roughly guess the purpose of this method. But this method is marked as
Deprecated. It has been replaced by $$ and methods. Regarding these two methods, we will talk about them later.