JavaScript examines the type of a variable and determines whether it is an integer or a string or other type, and so on.
<ptml> <pead> <title> Check variable type </title> </pead> <body> <script language= "Javascr IPT "> <!--name =" Liu Honghui "; age = 22; The type of the document.write (' name variable is: ', typeof (name), '); The type of document.write (' Age variable is: ', typeof (age), '); document.write (' Document of type is: ', typeof (document)); --> </script> </body> </ptml>
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2, toString is used to do string conversion, but now popular to do variable type of check. Shun also wrote a function to check the type of variable, which can be used instead of typeof
Copy Code code as follows:
function GetType (o) {
var _t; Return ((_t = typeof (o)) = = "Object"? O==null && "Null" | | Object.prototype.toString.call (o). Slice (8,-1): _t). toLowerCase ();
}
Execution results:
GetType ("abc"); String
GetType (TRUE); Boolean
GetType (123); Number
GetType ([]); Array
GetType ({}); Object
GetType (function () {}); function
GetType (new Date); Date
GetType (new REGEXP); Regexp
GetType (Math); Math
GetType (NULL); Null
