day2_3.html

javascript的学习文章

    <td colspan="2" align="center" bgcolor="#666699"><a href="../../1-download/index.htm"><font color="#FFFFFF">网猴下载</font></a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-download/page1.htm">网页制作</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<font color="#000000"><a href="../../1-download/page2.htm">程序设计</a></font></td>
  </tr>
  <tr> 
    <td colspan="2">-<font color="#000000"><a href="../../1-download/page3.htm">网站设计</a></font></td>
  </tr>
  <tr> 
    <td colspan="2">-<font color="#000000"><a href="../../1-download/page4.htm">电子商务</a></font> 
    </td>
  </tr>
  <tr> 
    <td colspan="2" align="center" bgcolor="#666699"><a href="../../1-teach/index.htm"><font color="#FFFFFF">实用技巧</font></a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/internet/index.htm">Internet应用</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/photoshop/index.html">Photoshop</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/flash/page1.html">Flash</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/asp/index.html">ASP</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/php/index.html">PHP</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/java/index.htm">Java</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/vb/index.htm">VB</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/c/index.htm">C、C++</a></td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-backend/database/php_mysql/index.html">PHP/MySQL</a></td>
  </tr>
  <tr> 
    <td colspan="2"><a href="../../1-backend/cgi_perl/perl_beginner/index.html">-Perl</a> 
    </td>
  </tr>
  <tr> 
    <td colspan="2">-<a href="../../1-teach/other/index.htm">其它</a> </td>
  </tr>
  <tr> 
    <td colspan="2" bgcolor="#666699"> 
      <div align="center"><font color="#FFFFFF">更多教程</font></div>
    </td>
  </tr>
  <tr> 
    <td colspan="2" height="17"><a href="../../1hdml/index.html">-HDML</a></td>
  </tr>
  <tr> 
    <td colspan="2" height="23"><font face="宋体"><a href="../../1-backend/database/course/day1_1.html">-网络数据库</a></font></td>
  </tr>
  <tr> 
    <td colspan="2" height="14"><a href="../../1-backend/protocols/ping/index.html"><font face="arial, helvetica, sans-serif">Ping</font></a></td>
  </tr>
  <tr> 
    <td colspan="2" height="20"><a href="../../1-backend/cgi_perl/search_engine/index.html">-创建搜索引擎</a></td>
  </tr>
  <tr> 
    <td colspan="2" height="16">-<a href="../../1adobe/GoLive/index.html">Adobe GoLive</a></td>
  </tr>
  <tr> 
    <td colspan="2"><a href="../../1-backend/cgi_perl/templates/index.html">模板</a></td>
  </tr>
  <tr> 
    <td colspan="2" align="center" bgcolor="#666699"><font color="#FFFFFF">合作伙伴</font></td>
  </tr>
  <tr> 
    <td colspan="2" align="left">-<a href="http://www.5dmedia.com/" target="_blank">5D精英网</a></td>
  </tr>
  <tr align="center"> 
    <td colspan="2"> <img src="../../Library/front_monkey.gif" width="59" height="68"></td>
  </tr>
  </tbody> 
</table>
<br><!-- #EndLibraryItem --></td>
      <!-- End of headlines (column 1: left column) --> <!-- Gutter between columns 1 and 2 --> 
      <td width="10" height="794"><img src="http://www.sohu.com/images/pixel.gif" width=10></td>
      <!-- Search box and directories (columns 2 and 3: middle columns, combined into one) --> 
      <td align=center valign=top width="558"> 
        <div align="left"><!-- #BeginEditable "1" --> 
          <title>javascrip教程</title>
          <strong><font face="宋体" size="3">第三页：首个变量例子的程序主体</font></strong> 
          <p><font face="宋体" size="3">现在我们已经定义了变量，让我们用它来做一些事。</font></p>
          <blockquote> 
            <pre><font face="宋体" size="3">
&lt;script language=&quot;JavaScript&quot;&gt;

&lt;!-- hide me

</font></pre>
          </blockquote>
          <p><font face="宋体" size="3">这里介绍如何用JavaScript写变量和网页。</font></p>
          <blockquote> 
            <pre><font face="宋体" size="3">
// here's how to use JavaScript to write out HTML

document.writeln(&quot;&lt;b&gt;The monkey dances &quot;);

document.writeln(secs_per_year);

document.writeln(&quot; seconds per year.&lt;/b&gt;&lt;p&gt;&quot;);

</font></pre>
          </blockquote>
          <p><font face="宋体" size="3">这里是关于这三行的兴趣点：</font> 
          <dl> 
            <dt><font face="宋体" size="3"><tt>document.writeln()</tt> 对于网页写入插入词。</font></dt>
            <dd><font face="宋体"><font size="3">在<tt>document.writeln()</tt></font><tt><font size="4">中可作大量细节之事，但到此为止<br>
              你只需记住你是在</font><font size="3">&lt;script&gt;</font></tt><font size="3">和<tt>&lt;/script&gt;</tt></font><tt><font size="4">标签之间，必须<br>
              用</font><font size="3">document.writeln(&quot;blah!&quot;)</font></tt><font size="3">在网页中写HTML</font></font></dd>
          </dl>
          <p><font face="宋体" size="3">引号中的字符显现出来；引号外的字符被认为是变量。</font> 
          <dl> 
            <dd><font face="宋体" size="3">注意在第一和第三行中，引号中的是我们想要显现的，<br>
              而<tt>secs_per_year</tt>无引号。因此JavaScript认为它是变量<br>
              并交换成变量值。幸好，在头文件中我们定义<br>
              了<tt>secs_per_year</tt>是一大数，因此可被显现，否<br>
              则JavaScript将报错。</font> 
              <p><font face="宋体" size="3">引号中的任何字都被称为字符串，JavaScript不编译它。<br>
                本例中使用的是双引号(<tt>&quot;</tt>)，也可使用单引号(<tt>'</tt>)，二者可<br>
                互换。若第二行中的是<br>
                <tt>document.writeln(&quot;secs_per_year&quot;)</tt>，JavaScript<br>
                将直接将<tt>secs_per_year</tt>显现，而不是<tt>31,536,000</tt>.</font></p>
              <p><font face="宋体" size="3">本例和字符的区别很重要，因此在我们继续下去之前，保<br>
                证你已读懂了这段。</font></p>
            </dd>
            <dt><font face="宋体" size="3">你可以用<tt>document.writeln()</tt> 写HTML语言。</font></dt>
            <dd><font face="宋体" size="3">注意第一和第三行的<tt>&lt;b&gt;</tt> 和 <tt>&lt;/b&gt;</tt> 
              标签。</font></dd>
          </dl>
          <p><font face="宋体" size="3">这即是该例的概要。我们常见的一个问题是：“通常什么出现<br>
            在头文件中，什么出现在主体文件中？”</font></p>
          <p><font face="宋体"><font size="3">一般这关系不大。好的习惯是把大多数JavaScript放在页面的<br>
            头上。这是因为比主体要先读到，所以出现在主体中的变量<br>
            (如<tt>secs_per_min</tt>)都在头中定义了。当<tt>secs_per_min</tt><br>
            在JavaScript试图执行<tt>document.writeln(secs_per_min)</tt></font><tt><font size="4">命令<br>
            后定义则</font></tt><font size="3">JavaScript会报错。</font></font></p>
          <p><font face="宋体" size="3">好，现在我们准备作一个关于变量的练习，但首先再注意一下<br>
            <a href="day2_4.html">字符串</a>。</font></p>
          <p align="left"><font face="宋体" size="3" color="#000000"><strong>JavaScript教程</strong></font><font color="#FF0000" face="宋体" size="3"><br>
            </font><font face="宋体" size="3"><font color="#FF0000">第一页</font>：<a href="day2_1.html">第二天课程简介</a><br>
            <font color="#FF0000">第二页</font>：<a href="day2_2.html">变量介绍</a><br>
            <font color="#FF0000">第三页</font>：首个变量例子的程序主体<br>
            <font color="#FF0000">第四页</font>：<a href="day2_4.html">字符串的魔力<br>
            </a><font color="#FF0000">第五页</font>：<a href="day2_5.html">变量练习</a><a href="day2_4.html"> 
            </a></font><font face="宋体" size="3"><br>
            <font color="#FF0000">第</font><font face="宋体" size="3"><font color="#FF0000">六</font></font><font color="#FF0000">页</font>：<a href="day2_6.html">if-then子句</a><br>
            <font color="#FF0000">第</font><font face="宋体" size="3"><font color="#FF0000">七</font></font><font color="#FF0000">页</font>：<a href="day2_7.html">if-then语句的例子</a> 
            <br>
            <font color="#FF0000">第八页</font>：<a href="day2_9.html">链结事件</a><br>
            <font color="#FF0000">第</font><font face="宋体" size="3"><font color="#FF0000">九</font></font><font color="#FF0000">页</font>：<a href="day2_10.html">图片交换</a><br>
            <font color="#FF0000">第十页</font>：<a href="day2_12.html">复习</a><br>
            </font></p>
          <p align="left"><font face="宋体" size="3">[<a href="index.html">第1课</a>][第2课][<a href="day3_1.html">第3课</a>][<a href="day4_1.html">第4课</a>][<a href="day5_1.html">第5课</a>]</font></p>
          <!-- #EndEditable --></div>
      </td>
      <!-- End of search box and directories (columns 2 and 3: middle columns, combined into one) --> 
      <!-- Gutter between columns 3 and 4 --> <!-- Other stuff (column 4: right column) --> 
      <!-- End of other stuff (column 4: right column) --> </tr>
  </table>
<!-- End of table surrounding page contents -->

  <hr noshade size=1 width=700>
 <span class=eng><br>
  Copyright (C) 1998-2000 Internet Technologies China.&nbsp; All rights reserved. 
  </span> 
</center>
</body>
<!-- #EndTemplate --></html>