stmt.html

javascript 1.5规范

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<A NAME="1015950"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><FONT FACE="courier, couriernew, monospaced size"><A HREF="stmt.html#1081298"  >break</A>, <A HREF="stmt.html#1018088"  >label</A></FONT></zparagraph>
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<A NAME="1037353"> </A>
<A NAME="do...while"> </A>
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<zhead1>do...while</zhead1>
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<A NAME="1057761"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Executes the specified statements until the test condition evaluates to false. Statements execute at least once. <BR>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1057766"> </A>
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<ztabletext>JavaScript 1.2, NES 3.0</ztabletext>
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<ztabletext>ECMA Version</ztabletext>
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<A NAME="1082047"> </A>
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<ztabletext>ECMA 262, Edition 3</ztabletext>
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<zrefheader>Syntax</zrefheader>
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<A NAME="1016011"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>do <br>
&nbsp;&nbsp;&nbsp;<I>statements<br>
</I>while (<I>condition</I>);
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<A NAME="1016014"> </A>
<A NAME="Parameters"> </A>
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<zrefheader>Parameters</zrefheader>
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<A NAME="1016015"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><BR>
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<zcodeline>statements
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<A NAME="1016322"> </A>
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<ztabletext>Block of statements that is executed at least once and is re-executed each time the condition evaluates to true. </ztabletext>
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<zcodeline>condition
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<ztabletext>Evaluated after each pass through the loop. If <FONT FACE="courier, couriernew, monospaced size">condition</FONT> evaluates to true, the statements in the preceding block are re-executed. When <FONT FACE="courier, couriernew, monospaced size">condition</FONT> evaluates to false, control passes to the statement following <FONT FACE="courier, couriernew, monospaced size">do while</FONT>. </ztabletext>
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<A NAME="1058838"> </A>
<A NAME="Examples"> </A>
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<zrefheader>Examples</zrefheader>
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<A NAME="1016021"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>In the following example, the <FONT FACE="courier, couriernew, monospaced size">do</FONT> loop iterates at least once and reiterates until i is no longer less than 5.</zparagraph>
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<A NAME="1016023"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>do {<br>
&nbsp;&nbsp;&nbsp;i+=1;<br>
&nbsp;&nbsp;&nbsp;document.write(i);<br>
while (i&lt;5);
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<A NAME="1016648"> </A>
<A NAME="export"> </A>
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<zhead1>export</zhead1>
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<A NAME="1082357"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Allows a signed script to provide properties, functions, and objects to other signed or unsigned scripts.</zparagraph>
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<A NAME="1082415"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>This feature is not in ECMA 262, Edition 3.<BR>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1035842"> </A>
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<ztabletext>JavaScript 1.2, NES 3.0</ztabletext>
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<A NAME="1016651"> </A>
<A NAME="Syntax"> </A>
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<A NAME="1016652"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>export name1, name2, ..., nameN<br>
export *
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<A NAME="1016655"> </A>
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<zrefheader>Parameters</zrefheader>
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<A NAME="1016656"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><BR>
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<zcodeline>nameN
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<A NAME="1016991"> </A>
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<ztabletext>List of properties, functions, and objects to be exported.</ztabletext>
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<zcodeline>*
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<A NAME="1033733"> </A>
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<ztabletext>Exports all properties, functions, and objects from the script.</ztabletext>
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<A NAME="Description"> </A>
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<zrefheader>Description</zrefheader>
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<A NAME="1016659"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Typically, information in a signed script is available only to scripts signed by the same principals. By exporting properties, functions, or objects, a signed script makes this information available to any script (signed or unsigned). The receiving script uses the companion import statement to access the information.</zparagraph>
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<A NAME="1016663"> </A>
<A NAME="See also"> </A>
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<A NAME="1016630"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><A HREF="stmt.html#1082618"  >import</A></zparagraph>
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<A NAME="1004804"> </A>
<A NAME="for"> </A>
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<zhead1>for</zhead1>
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<A NAME="1004805"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph>Creates a loop that consists of three optional expressions, enclosed in parentheses and separated by semicolons, followed by a block of statements executed in the loop.<BR>
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<ztabletext><I>Implemented in</I></ztabletext>
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<A NAME="1041845"> </A>
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<ztabletext>JavaScript 1.0, NES 2.0</ztabletext>
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<A NAME="1050127"> </A>
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<ztabletext><I>ECMA version</I></ztabletext>
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<A NAME="1050129"> </A>
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<ztabletext>ECMA-262</ztabletext>
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<A NAME="1004806"> </A>
<A NAME="Syntax"> </A>
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<A NAME="1004807"></A><FONT FACE="courier, couriernew, monospaced size" SIZE="2">
<zcodeline>for ([initial-expression]; [condition]; [increment-expression]) 
{<br>
&nbsp;&nbsp;&nbsp;statements<br>
}
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<A NAME="1004808"> </A><FONT FACE="Arial, Helvetica, sans-serif" SIZE="2"><zparagraph><BR>
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<zcodeline>initial-expression
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<ztabletext>Statement or variable declaration. Typically used to initialize a counter variable. This expression may optionally declare new variables with the <FONT FACE="courier, couriernew, monospaced size">var</FONT> keyword. These variables are local to the function, not to the loop.</ztabletext>
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<zcodeline>condition
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<ztabletext>Evaluated on each pass through the loop. If this condition evaluates to true, the statements in <FONT FACE="courier, couriernew, monospaced size">statements</FONT> are performed. This conditional test is optional. If omitted, the condition always evaluates to true.</ztabletext>
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<zcodeline>increment-expression
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<A NAME="1012459"> </A>
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<ztabletext>Generally used to update or increment the counter variable.</ztabletext>
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<zcodeline>statements
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<A NAME="1012492"> </A>
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<ztabletext>Block of statements that are executed as long as condition evaluates to true. This can be a single statement or multiple statements. Although not required, it is good practice to indent these statements from the beginning of the <FONT FACE="courier, couriernew, monospaced size">for</FONT> statement.</ztabletext>
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