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help with a w3 javascript


niche

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I don't understand this part of the javascript found at:http://www.w3schools.com/dhtml/tryit.asp?filename=trydhtml_menu10Please insert a few comments that might help me understand how this part of the script works(ie I don't see how this part of the script triggers so much) :

<script type="text/javascript">function showmenu(elmnt){document.getElementById(elmnt).style.visibility="visible";}function hidemenu(elmnt){document.getElementById(elmnt).style.visibility="hidden";}</script>

Here's the complete script:

<html><head><style>body{font-family:arial;}table{font-size:80%;background:black}a{color:black;text-decoration:none;font:bold}a:hover{color:#606060}td.menu{background:lightblue}table.menu{font-size:100%;position:absolute;visibility:hidden;}</style><script type="text/javascript">function showmenu(elmnt){document.getElementById(elmnt).style.visibility="visible";}function hidemenu(elmnt){document.getElementById(elmnt).style.visibility="hidden";}</script></head><body><h3>Drop down menu</h3><table width="100%"> <tr bgcolor="#FF8080">  <td onmouseover="showmenu('tutorials')" onmouseout="hidemenu('tutorials')">   <a href="/default.asp">Tutorials</a><br />   <table class="menu" id="tutorials" width="120">   <tr><td class="menu"><a href="/html/default.asp">HTML</a></td></tr>   <tr><td class="menu"><a href="/xhtml/default.asp">XHTML</a></td></tr>   <tr><td class="menu"><a href="/css/default.asp">CSS</a></td></tr>   <tr><td class="menu"><a href="/xml/default.asp">XML</a></td></tr>   <tr><td class="menu"><a href="/xsl/default.asp">XSL</a></td></tr>   </table>  </td>  <td onmouseover="showmenu('scripting')" onmouseout="hidemenu('scripting')">   <a href="/default.asp">Scripting</a><br />   <table class="menu" id="scripting" width="120">   <tr><td class="menu"><a href="/js/default.asp">JavaScript</a></td></tr>   <tr><td class="menu"><a href="/vbscript/default.asp">VBScript</a></td></tr>   <tr><td class="menu"><a href="default.asp">DHTML</a></td></tr>   <tr><td class="menu"><a href="/asp/default.asp">ASP</a></td></tr>   <tr><td class="menu"><a href="/ado/default.asp">ADO</a></td></tr>   </table>  </td>  <td onmouseover="showmenu('validation')" onmouseout="hidemenu('validation')">   <a href="/site/site_validate.asp">Validation</a><br />   <table class="menu" id="validation" width="120">   <tr><td class="menu"><a href="/site/site_validate.asp">Validate HTML</a></td></tr>   <tr><td class="menu"><a href="/site/site_validate.asp">Validate XHTML</a></td></tr>   <tr><td class="menu"><a href="/site/site_validate.asp">Validate CSS</a></td></tr>   <tr><td class="menu"><a href="/site/site_validate.asp">Validate XML</a></td></tr>   <tr><td class="menu"><a href="/site/site_validate.asp">Validate WML</a></td></tr>   </table>  </td> </tr></table><p>Mouse over these options to see the drop down menus</p></body></html>

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I've been looking at this some more and I don't understand how (elmnt) was determined and how .style.visibility="visible"; and .style.visibility="hidden"; was determined.

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I think I got on the path finally. I think I'm finding the answer in the DHTML section not the javascript. Please let me know if I'm wrong. Otherwise, I'll be studying DHTML.

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I think I got on the path finally. I think I'm finding the answer in the DHTML section not the javascript. Please let me know if I'm wrong. Otherwise, I'll be studying DHTML.

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elmnt is the id ref sent to the function, on mouseover and mouseout<script type="text/javascript">function showmenu(elmnt){document.getElementById(elmnt).style.visibility="visible";}function hidemenu(elmnt){document.getElementById(elmnt).style.visibility="hidden";}</script>example <td onmouseover="showmenu('tutorials')" onmouseout="hidemenu('tutorials')"> will target element with id ref id="tutorials"it is doing exactly as if it was written as document.getElementById("tutorials").style.visibility="visible";document.getElementById("tutorials").style.visibility="hidden";so on hover over (onmouseover) it show the table element below and its contents within that table, on onmouseout the table is now hidden.<table class="menu" id="tutorials" width="120"> .......</table>

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Note that "DHTML" is simply the use of JavaScript to modify the appearance of a web page.

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