javascript function expression

hoisting, read and add the function declaration to the execution environment. When you evaluate the code, the JavaScript engine declares the functions for the first time and places them on the top of the source code tree. Therefore, even if the declared function code is behind the code that calls it, the JavaScript en

hoisting, read and add the function declaration to the execution environment. When you evaluate the code, the JavaScript engine declares the functions for the first time and places them on the top of the source code tree. Therefore, even if the declared function code is behind the code that calls it, the JavaScript en

list of this article is as follows: How should we understand the working principle of the JavaScript engine? JavaScript exploration: the importance of writing maintainable code JavaScript exploration: exercise caution when using global variables JavaScript exploration: var pre-parsing and side effects

");}(); Unfortunately, the preceding Writing Method reports a js syntax error. Because when the Javascript parser parses the global function or function internal function keywords, the braces are parsed into function declarations by default, instead of

function declaration function foo () {} The function foo will be hoist (promoted) before the entire program executes, so it is available in the entire scope (scope) that defines the Foo function. It is fine even if you call it before the function definition.

the function can be invoked correctly. But this loosening is not conducive to rigorous coding, and in the long run it is likely to promote rather than prevent accidents from happening. After all, there is a reason why programmers arrange statements in a particular order. Is there any other reason to support Function Expression? You know what? 1

When you usually use JS to write functions, it is generally customary function fn () {} to declare a function, in reading some excellent plug-ins when you see the var fn = function () {} the creation of such functions, exactly what they What is the difference between using it, today in the spirit of breaking the sand pot to ask the end, well say this fascinating-

Copy Code code as follows: function Checkmobile () { var smobile = Document.mobileform.mobile.value if (!) ( /^1[3|4|5|8][0-9]\d{4,8}$/.test (Smobile))) { Alert ("Not a full 11-digit cell phone number or the correct number of the top seven"); Document.mobileform.mobile.focus (); return false; } } The following is the cloud Habitat Community editors on the above regular expression