Implementation and advantages of JavaScript function inert loading _ javascript skills

Inert loading indicates that the branch of the function execution will only be executed when the function is used for the first time. During the first call, the function will be overwritten as another function to be executed in an appropriate way, in this way, any call to the original function does not need to go through the branch of the execution. Recently, I have been reading JavaScript advanced program design, which is a great achievement. I will take some reading notes in the next few days. I wrote an article about Ajax preliminary understanding. There is a function in it to create the XmlHttpRequest object. The reason for browser compatibility is that the code written is judged by a large number of if statements or try statements, the catch statement directs the function to the correct code.

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