regexp.html

javascript 1.5规范

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<zcodeline><A HREF="regexp.html#1194735"  >exec</A>
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<A NAME="1193556"> </A>
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<ztabletext>Executes a search for a match in its string parameter. </ztabletext>
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    <TD VALIGN=TOP><A NAME="1193561"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline><A HREF="regexp.html#1194128"  >test</A>
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<A NAME="1193563"> </A>
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<ztabletext>Tests for a match in its string parameter. </ztabletext>
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    <TD VALIGN=TOP><A NAME="1193568"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline><A HREF="regexp.html#1194174"  >toSource</A>
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<A NAME="1193570"> </A>
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<ztabletext>Returns an object literal representing the specified object; you can use this value to create a new object. Overrides the <A HREF="object.html#1193320"  >Object.toSource</A> method.</ztabletext>
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    <TD VALIGN=TOP><A NAME="1199185"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline><A HREF="regexp.html#1199205"  >toString</A>
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<A NAME="1199187"> </A>
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<ztabletext>Returns a string representing the specified object. Overrides the <A HREF="object.html#1193350"  >Object.toString</A> method.</ztabletext>
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<A NAME="1200128"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>In addition, this object inherits the <A HREF="object.html#1193628"  >watch</A> and <A HREF="object.html#1193499"  >unwatch</A> methods from <A HREF="object.html#1193136"  >Object</A>.</zparagraph>
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<A NAME="1193572"> </A>
<A NAME="Examples"> </A>
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<zrefheader>Examples</zrefheader>
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<A NAME="1193574"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><B>Example 1.</B> The following script uses the <FONT FACE="courier, couriernew, monospaced size">replace</FONT> method to switch the words in the string. In the replacement text, the script uses "$1" and "$2" to indicate the results of the corresponding matching parentheses in the regular expression pattern. </zparagraph>
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<A NAME="1193575"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>&lt;SCRIPT&gt;<br>
re = /(\w+)\s(\w+)/;<br>
str = "John Smith";<br>
newstr=str.replace(re, "$2, $1");<br>
document.write(newstr)<br>
&lt;/SCRIPT&gt;
</zcodeline>
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<A NAME="1193576"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>This displays "Smith, John". </zparagraph>
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<A NAME="1193578"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><B>Example 2.</B> In the following example, <FONT FACE="courier, couriernew, monospaced size">RegExp.input</FONT> is set by the Change event. In the <FONT FACE="courier, couriernew, monospaced size">getInfo</FONT> function, the <FONT FACE="courier, couriernew, monospaced size">exec</FONT> method uses the value of <FONT FACE="courier, couriernew, monospaced size">RegExp.input</FONT> as its argument. </zparagraph>
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<A NAME="1193579"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>&lt;HTML&gt;
</zcodeline>
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<P><A NAME="1193580"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>&lt;SCRIPT&gt;<br>
function getInfo() {<br>
&nbsp;&nbsp;&nbsp;re = /(\w+)\s(\d+)/;<br>
&nbsp;&nbsp;&nbsp;var m = re.exec();<br>
&nbsp;&nbsp;&nbsp;window.alert(m[] + ", your age is " + m[2]);<br>
}<br>
&lt;/SCRIPT&gt;
</zcodeline>
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<P><A NAME="1193581"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>Enter your first name and your age, and then press Enter.
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<P><A NAME="1193582"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>&lt;FORM&gt;<br>
&lt;INPUT TYPE:"TEXT" NAME="NameAge" onChange="getInfo(this);"&gt;<br>
&lt;/FORM&gt;
</zcodeline>
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<P><A NAME="1193583"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>&lt;/HTML&gt;
</zcodeline>
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<A NAME="1213253"> </A>
<A NAME="constructor"> </A>
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<zrefhead2>constructor</zrefhead2>
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<A NAME="1200249"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Specifies the function that creates an object's prototype. Note that the value of this property is a reference to the function itself, not a string containing the function's name.<BR>
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<A NAME="1200252"> </A>
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<ztabletext><I>Property of</I></ztabletext>
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<A NAME="1200257"> </A>
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<ztabletext><A HREF="regexp.html#1193136"  >RegExp</A></ztabletext>
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<A NAME="1200259"> </A>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1200261"> </A>
<FONT FACE="Arial, Helvetica, sans-serif" SIZE="2">
<ztabletext>JavaScript 1.1, NES 2.0</ztabletext>
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<A NAME="1200263"> </A>
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<ztabletext><I>ECMA version</I></ztabletext>
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<A NAME="1200265"> </A>
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<ztabletext>ECMA-262</ztabletext>
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<A NAME="1200266"> </A>
<A NAME="Description"> </A>
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<zrefheader>Description</zrefheader>
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<A NAME="1200270"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>See <A HREF="object.html#1193229"  >Object.constructor</A>.</zparagraph>
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<A NAME="1194735"> </A>
<A NAME="exec"> </A>
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<B>
<zrefhead2>exec</zrefhead2>
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<A NAME="1194748"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Executes the search for a match in a specified string. Returns a result array.<BR>
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<A NAME="1194738"> </A>
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<ztabletext><I>Method of</I></ztabletext>
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<A NAME="1194743"> </A>
<FONT FACE="Arial, Helvetica, sans-serif" SIZE="2">
<ztabletext><A HREF="regexp.html#1193136"  >RegExp</A></ztabletext>
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<A NAME="1194745"> </A>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1194747"> </A>
<FONT FACE="Arial, Helvetica, sans-serif" SIZE="2">
<ztabletext>JavaScript 1.2, NES 3.0</ztabletext>
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<A NAME="1208475"> </A>
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<ztabletext>ECMA version</ztabletext>
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<A NAME="1208477"> </A>
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<ztabletext>ECMA 262, Edition 3 (first syntax only)</ztabletext>
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<A NAME="1194749"> </A>
<A NAME="Syntax"> </A>
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<zrefheader>Syntax</zrefheader>
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<A NAME="1194750"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline><I>regexp</I>.exec([<I>str</I>])<br>
<I>regexp</I>([<I>str</I>])
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<A NAME="1194751"> </A>
<A NAME="Parameters"> </A>
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<zrefheader>Parameters</zrefheader>
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<A NAME="1194764"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><BR>
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<zcodeline>regexp
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<A NAME="1194756"> </A>
<FONT FACE="Arial, Helvetica, sans-serif" SIZE="2">
<ztabletext><FONT FACE="courier, couriernew, monospaced size">The </FONT>name of the regular expression. It can be a variable name or a literal. </ztabletext>
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<zcodeline>str
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<A NAME="1194760"> </A>
<FONT FACE="Arial, Helvetica, sans-serif" SIZE="2">
<ztabletext>The string against which to match the regular expression. </ztabletext>
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<A NAME="1194765"> </A>
<A NAME="Description"> </A>
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<zrefheader>Description</zrefheader>
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<A NAME="1194766"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>As shown in the syntax description, a regular expression's <FONT FACE="courier, couriernew, monospaced size">exec</FONT> method can be called either directly, (with <FONT FACE="courier, couriernew, monospaced size">regexp.exec(str)</FONT>) or indirectly (with <FONT FACE="courier, couriernew, monospaced size">regexp(str)</FONT>).</zparagraph>
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<A NAME="1194770"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>If you are executing a match simply to find <FONT FACE="courier, couriernew, monospaced size">true</FONT> or <FONT FACE="courier, couriernew, monospaced size">false</FONT>, use the <A HREF="regexp.html#1194128"  >test</A> method or the <FONT FACE="courier, couriernew, monospaced size">String</FONT> <A HREF="string.html#1194332"  >search</A> method. </zparagraph>
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<A NAME="1194774"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>If the match succeeds, the <FONT FACE="courier, couriernew, monospaced size">exec</FONT> method returns an array and updates properties of the regular expression object. If the match fails, the <FONT FACE="courier, couriernew, monospaced size">exec</FONT> method returns <FONT FACE="courier, couriernew, monospaced size">null</FONT>. </zparagraph>
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<A NAME="1194775"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Consider the following example: </zparagraph>
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<A NAME="1194776"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>&lt;SCRIPT LANGUAGE="JavaScript1.2"&gt;<br>
//Match one d followed by one or more b's followed by one d<br>
//Remember matched b's and the following d<br>
//Ignore case<br>
myRe=/d(b+)(d)/ig;<br>
myArray = myRe.exec("cdbBdbsbz");<br>
&lt;/SCRIPT&gt;
</zcodeline>
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