array.html

javascript 1.5规范

<A NAME="1193429"> </A>
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<ztabletext><A HREF="array.html#1193137"  >Array</A></ztabletext>
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<ztabletext><I>Static</I></ztabletext>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1193437"> </A>
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<ztabletext>JavaScript 1.2, NES 3.0</ztabletext>
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<A NAME="1195456"> </A>
<A NAME="join"> </A>
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<zrefhead2>join</zrefhead2>
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<A NAME="1195470"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Joins all elements of an array into a string.<BR>
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<ztabletext><I>Method of</I></ztabletext>
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<A NAME="1195465"> </A>
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<ztabletext><A HREF="array.html#1193137"  >Array</A></ztabletext>
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<A NAME="1195467"> </A>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1195469"> </A>
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<ztabletext>JavaScript 1.1, NES 2.0</ztabletext>
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<ztabletext><I>ECMA version</I></ztabletext>
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<A NAME="1198306"> </A>
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<ztabletext>ECMA-262</ztabletext>
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<A NAME="1195471"> </A>
<A NAME="Syntax"> </A>
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<zrefheader>Syntax</zrefheader>
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<A NAME="1195472"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>join(<I>separator</I>)
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<A NAME="1195473"> </A>
<A NAME="Parameters"> </A>
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<zrefheader>Parameters</zrefheader>
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<A NAME="1195479"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><BR>
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<zcodeline>separator
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<A NAME="1195478"> </A>
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<ztabletext>Specifies a string to separate each element of the array. The separator is converted to a string if necessary. If omitted, the array elements are separated with a comma.</ztabletext>
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<A NAME="1195480"> </A>
<A NAME="Description"> </A>
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<zrefheader>Description</zrefheader>
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<A NAME="1195481"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>The string conversions of all array elements are joined into one string.</zparagraph>
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<A NAME="1195482"> </A>
<A NAME="Examples"> </A>
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<zrefheader>Examples</zrefheader>
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<A NAME="1195483"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>The following example creates an array, <FONT FACE="courier, couriernew, monospaced size">a</FONT>, with three elements, then joins the array three times: using the default separator, then a comma and a space, and then a plus.</zparagraph>
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<A NAME="1206975"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>a = new Array("Wind","Rain","Fire")<br>
myVar1=a.join()&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// assigns "Wind,Rain,Fire" to myVar1<br>
myVar2=a.join(", ")&nbsp;&nbsp;// assigns "Wind, Rain, Fire" to myVar1<br>
myVar3=a.join(" + ")&nbsp;// assigns "Wind + Rain + Fire" to myVar1
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<A NAME="1195487"> </A>
<A NAME="See also"> </A>
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<zrefheader>See also</zrefheader>
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<A NAME="1195491"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><A HREF="array.html#1193641"  >Array.reverse</A></zparagraph>
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<A NAME="1193439"> </A>
<A NAME="length"> </A>
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<zrefhead2>length</zrefhead2>
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<A NAME="1193454"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>An unsigned, 32-bit integer that specifies the number of elements in an array.<BR>
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<A NAME="1193443"> </A>
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<ztabletext><I>Property of</I></ztabletext>
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<A NAME="1193448"> </A>
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<ztabletext><A HREF="array.html#1193137"  >Array</A></ztabletext>
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<A NAME="1193450"> </A>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1193452"> </A>
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<ztabletext>JavaScript 1.1, NES 2.0</ztabletext>
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<A NAME="1198137"> </A>
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<A NAME="1193453"> </A>
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<ztabletext>JavaScript 1.3: <FONT FACE="courier, couriernew, monospaced size">length</FONT> is an unsigned, 32-bit integer with a value less than 2<SUP>32</SUP>.</ztabletext>
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<ztabletext><I>ECMA version</I></ztabletext>
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<ztabletext>ECMA-262</ztabletext>
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<A NAME="Description"> </A>
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<zrefheader>Description</zrefheader>
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<A NAME="1193456"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>The value of the <FONT FACE="courier, couriernew, monospaced size">length</FONT> property is an integer with a positive sign and a value less than 2 to the 32 power (2<SUP>32</SUP>).</zparagraph>
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<A NAME="1193457"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>You can set the <FONT FACE="courier, couriernew, monospaced size">length</FONT> property to truncate an array at any time. When you extend an array by changing its <FONT FACE="courier, couriernew, monospaced size">length</FONT> property, the number of actual elements does not increase; for example, if you set <FONT FACE="courier, couriernew, monospaced size">length</FONT> to 3 when it is currently 2, the array still contains only 2 elements.</zparagraph>
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<A NAME="Examples"> </A>
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<zrefheader>Examples</zrefheader>
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<A NAME="1213262"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>In the following example, the <FONT FACE="courier, couriernew, monospaced size">getChoice</FONT> function uses the <FONT FACE="courier, couriernew, monospaced size">length</FONT> property to iterate over every element in the <FONT FACE="courier, couriernew, monospaced size">musicType</FONT> array. <FONT FACE="courier, couriernew, monospaced size">musicType</FONT> is a select element on the <FONT FACE="courier, couriernew, monospaced size">musicForm</FONT> form.</zparagraph>
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<A NAME="1213264"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>function getChoice() {<br>
&nbsp;&nbsp;&nbsp;for (var i = 0; i &lt; document.musicForm.musicType.length; i++) {<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (document.musicForm.musicType.options[i].selected == true) {<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return document.musicForm.musicType.options[i].text<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br>
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}
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<A NAME="1193461"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>The following example shortens the array <FONT FACE="courier, couriernew, monospaced size">statesUS</FONT> to a length of 50 if the current length is greater than 50.</zparagraph>
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<A NAME="1193462"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>if (statesUS.length &gt; 50) {<br>
&nbsp;&nbsp;&nbsp;statesUS.length=50<br>
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<A NAME="1196003"> </A>
<A NAME="pop"> </A>
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<zrefhead2>pop</zrefhead2>
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<A NAME="1196005"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Removes the last element from an array and returns that element. This method changes the length of the array.<BR>
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<ztabletext><I>Method of</I></ztabletext>
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<A NAME="1196013"> </A>
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<ztabletext><A HREF="array.html#1193137"  >Array</A></ztabletext>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1196017"> </A>
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<ztabletext>JavaScript 1.2, NES 3.0</ztabletext>
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<ztabletext><I>ECMA version</I></ztabletext>
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<A NAME="1220477"> </A>
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<ztabletext>ECMA-262 Edition 3</ztabletext>
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<A NAME="Syntax"> </A>
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<zrefheader>Syntax</zrefheader>
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<zcodeline>pop()
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<zrefheader>Parameters</zrefheader>
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<A NAME="1196021"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>None. </zparagraph>
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