Firebug adds a global variable named "console" to all web pages loaded in Firefox. This object contains many methods that allow you to write to the Firebug console to expose information th
===与!== ===代表恒等于,不仅判断数值,而且判断类型。比如 var a=5,b="5"; document.write(a==b); document.write(a===b); 结果 true false a是数值类型,b是字符串类型,虽然数值相等但是类型不等。 a==b //
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