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"JavaScript advanced Programming" reading notes

Source: Internet
Author: User
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Chapter II

1 <script type= "text/javascript" Async defer src= "" ></script> defer: Delay script until the document is fully parsed and displayed before execution, but download now, preferably with only one. Async: Indicates that the script should be downloaded immediately, but should not interfere with other actions on the page, and is not guaranteed to be executed in the order in which they were specified, and the asynchronous script must be executed before the page's Load event

2 Browser parsing: The rest of the page will not be loaded or displayed by the browser until all code inside the <script> element is evaluated by the interpreter. When parsing an external JavaScript file (including downloading the file), the processing of the page is temporarily stopped. The browser only starts rendering content when it encounters a <body> tag

Chapter III

1 everything in ECMAScript (variables, function names, and operators) is case-sensitive

"JavaScript advanced Programming" reading notes

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