09 2017 档案
摘要：var p = {// x and y are regular read-write data properties.x: 1.0,y: 1.0,r:function () { return Math.sqrt( x*x + y*y); }, }; 如果调用 p.r()，会报错的， r函数里面必须要
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摘要：Testing Properties To check whether an object has a property with a given name. You can do this with the in operator, with the hasOwnProperty() and pr
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摘要：Logical AND (&&) The && operator can be understood at three different levels. At the simplest level, when used with boolean operands, && performs the
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摘要：The Scope Chain JavaScript is a lexically scoped language: the scope of a variable can be thought of as the set of source code lines for which the var
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摘要：Variables As Properties When you declare a global JavaScript variable, what you are actually doing is defining a property of the global object . If yo
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