function.html

javascript 1.5规范

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<zcodeline>// since 5000 is above 1000, value will be 999<br>
car = new prod_dept("honda", 5000, "auto");
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<A NAME="See also"> </A>
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<zrefheader>See also</zrefheader>
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<A NAME="1194060"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><A HREF="function.html#1194243"  >Function.call</A></zparagraph>
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<A NAME="1193312"> </A>
<A NAME="arguments"> </A>
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<zrefhead2>arguments</zrefhead2>
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<A NAME="1193325"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>An array corresponding to the arguments passed to a function.<BR>
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<A NAME="1228902"> </A>
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<ztabletext><I>Local variable of</I></ztabletext>
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<A NAME="1228907"> </A>
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<ztabletext>All function objects</ztabletext>
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<A NAME="1193315"> </A>
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<ztabletext><I>Property of</I></ztabletext>
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<A NAME="1193320"> </A>
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<ztabletext><A HREF="function.html#1193137"  >Function</A> (deprecated)</ztabletext>
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<A NAME="1193322"> </A>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1193324"> </A>
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<ztabletext>JavaScript 1.1, NES 2.0</ztabletext>
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<A NAME="1194829"> </A>
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<ztabletext></ztabletext>
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<A NAME="1194830"> </A>
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<ztabletext>JavaScript 1.2: added <A HREF="function.html#1196419"  >arguments.callee</A> property.</ztabletext>
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<A NAME="1210050"> </A>
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<ztabletext></ztabletext>
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<A NAME="1212031"> </A>
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<ztabletext>JavaScript 1.3: deprecated <A HREF="function.html#1196447"  >arguments.caller</A> property; removed support for argument names and local variable names as properties of the <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array.</ztabletext>
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<A NAME="1212032"> </A>
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<A NAME="1210081"> </A>
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<ztabletext>JavaScript 1.4: deprecated <FONT FACE="courier, couriernew, monospaced size">arguments</FONT>, <A HREF="function.html#1196419"  >arguments.callee</A>, and <A HREF="function.html#1196484"  >arguments.length</A> as properties of <FONT FACE="courier, couriernew, monospaced size">Function</FONT>; retained <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> as a local variable of a function and <A HREF="function.html#1196419"  >arguments.callee</A> and <A HREF="function.html#1196484"  >arguments.length</A> as properties of this variable.</ztabletext>
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<A NAME="1196948"> </A>
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<ztabletext><I>ECMA version</I></ztabletext>
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<A NAME="1196950"> </A>
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<ztabletext>ECMA-262</ztabletext>
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<A NAME="1211023"> </A>
<A NAME="Description"> </A>
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<zrefheader>Description</zrefheader>
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<A NAME="1230788"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>The <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array is a local variable available within all function objects; <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> as a property of <FONT FACE="courier, couriernew, monospaced size">Function</FONT> is no longer used.</zparagraph>
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<A NAME="1229024"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>You can refer to a function's arguments within the function by using the <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array. This array contains an entry for each argument passed to the function. For example, if a function is passed three arguments, you can refer to the arguments as follows:</zparagraph>
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<A NAME="1229025"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>arguments[0]<br>
arguments[1]<br>
arguments[2]
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<A NAME="1229074"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>The <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array is available only within a function body. Attempting to access the <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array outside a function declaration results in an error.</zparagraph>
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<A NAME="1229290"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>You can use the <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array if you call a function with more arguments than it is formally declared to accept. This technique is useful for functions that can be passed a variable number of arguments. You can use <FONT FACE="courier, couriernew, monospaced size">arguments.length</FONT> to determine the number of arguments passed to the function, and then process each argument by using the <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array. (To determine the number of arguments declared when a function was defined, use the <A HREF="function.html#1216661"  >Function.length</A> property.)</zparagraph>
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<A NAME="1193330"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>The <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array has the following properties:</zparagraph>
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<A NAME="1211223"> </A>
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<ztablehead>Property</ztablehead>
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    <TH VALIGN=TOP ALIGN=LEFT><A NAME="1211172"> </A>
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<ztablehead>Description</ztablehead>
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<A NAME="1211177"> </A>
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<ztabletext><A HREF="function.html#1196419"  >arguments.callee</A></ztabletext>
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<A NAME="1211179"> </A>
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<ztabletext>Specifies the function body of the currently executing function.</ztabletext>
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<A NAME="1211184"> </A>
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<ztabletext><A HREF="function.html#1196447"  >arguments.caller</A></ztabletext>
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<A NAME="1211186"> </A>
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<ztabletext>Specifies the name of the function that invoked the currently executing function. (Deprecated)</ztabletext>
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<A NAME="1211191"> </A>
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<ztabletext><A HREF="function.html#1196484"  >arguments.length</A></ztabletext>
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<A NAME="1211193"> </A>
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<ztabletext>Specifies the number of arguments passed to the function.</ztabletext>
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<A NAME="1211676"> </A>
<A NAME="Backward Compatibility"> </A>
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<zrefheader>Backward Compatibility</zrefheader>
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<A NAME="1228978"> </A>
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<zheadrunin>JavaScript 1.3 and earlier versions. </zheadrunin>
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<A NAME="1228979"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>In addition to being available as a local variable, the <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array is also a property of the <FONT FACE="courier, couriernew, monospaced size">Function</FONT> object and can be preceded by the function name. For example, if a function <FONT FACE="courier, couriernew, monospaced size">myFunc</FONT> is passed three arguments named <FONT FACE="courier, couriernew, monospaced size">arg1</FONT>, <FONT FACE="courier, couriernew, monospaced size">arg2</FONT>, and <FONT FACE="courier, couriernew, monospaced size">arg3</FONT>, you can refer to the arguments as follows:</zparagraph>
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<A NAME="1229046"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>myFunc.arguments[0]<br>
myFunc.arguments[1]<br>
myFunc.arguments[2]
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<A NAME="1211677"> </A>
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<zheadrunin>JavaScript 1.1 and 1.2. </zheadrunin>
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<A NAME="1212477"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>The following features, which were available in JavaScript&nbsp;1.1 and JavaScript&nbsp;1.2, have been removed:</zparagraph>
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<A NAME="1214329"> </A>
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<B>  <li></B>
<zsmartlist1>Each local variable of a function is a property of the <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array. For example, if a function <FONT FACE="courier, couriernew, monospaced size">myFunc</FONT> has a local variable named <FONT FACE="courier, couriernew, monospaced size">myLocalVar</FONT>, you can refer to the variable as <FONT FACE="courier, couriernew, monospaced size">arguments.myLocalVar</FONT>.</zsmartlist1>
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<B>  <li></B>
<zsmartlist1>Each formal argument of a function is a property of the <FONT FACE="courier, couriernew, monospaced size">arguments</FONT> array. For example, if a function <FONT FACE="courier, couriernew, monospaced size">myFunc</FONT> has two arguments named <FONT FACE="courier, couriernew, monospaced size">arg1</FONT> and <FONT FACE="courier, couriernew, monospaced size">arg2</FONT>, you can refer to the arguments as <FONT FACE="courier, couriernew, monospaced size">arguments.arg1</FONT> and <FONT FACE="courier, couriernew, monospaced size">arguments.arg2</FONT>. (You can also refer to them as <FONT FACE="courier, couriernew, monospaced size">arguments[0]</FONT> and <FONT FACE="courier, couriernew, monospaced size">arguments[1]</FONT>.)</zsmartlist1>
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<A NAME="Examples"> </A>
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<zrefheader>Examples</zrefheader>
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<A NAME="1229844"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><B>Example 1.</B> This example defines a function that concatenates several strings. The only formal argument for the function is a string that specifies the characters that separate the items to concatenate. The function is defined as follows:</zparagraph>
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<A NAME="1229845"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>function myConcat(separator) {<br>
&nbsp;&nbsp;&nbsp;result="" // initialize list<br>
&nbsp;&nbsp;&nbsp;// iterate through arguments<br>
&nbsp;&nbsp;&nbsp;for (var i=1; i&lt;arguments.length; i++) {<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;result += arguments[i] + separator<br>
&nbsp;&nbsp;&nbsp;}<br>
&nbsp;&nbsp;&nbsp;return result<br>
}
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<A NAME="1229846"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>You can pass any number of arguments to this function, and it creates a list using each argument as an item in the list.</zparagraph>
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<A NAME="1229847"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>// returns "red, orange, blue, "<br>
myConcat(", ","red","orange","blue")
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<P><A NAME="1229848"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>// returns "elephant; giraffe; lion; cheetah;"<br>
myConcat("; ","elephant","giraffe","lion", "cheetah")
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<P><A NAME="1229849"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>// returns "sage. basil. oregano. pepper. parsley. "<br>
myConcat(". ","sage","basil","oregano", "pepper", "parsley")
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