我無法使用我的網頁瀏覽位於JScript中的選擇列表中的網址。

我有一個JavaScript作業分配，需要導航到位於選擇列表中的選定URL。我以爲我有這個下來，但卡住了。我將列出作業的方向，以便有人可以根據課程計劃查明我的錯誤。任何幫助將不勝感激！我無法使用我的網頁瀏覽位於JScript中的選擇列表中的網址。

創建init（）函數。在此功能中，執行以下操作： a）創建一個名爲allSelect的變量，該變量引用文檔中的所有選擇元素。 b）對於allSelect對象集合中的每個項目，添加一個onchange事件處理程序，當選擇列表更改時運行loadLink（）函數。

創建loadLink（）函數。此功能的目的是使瀏覽器從選擇列表中加載URL。將以下命令添加到該函數中： a）創建一個名爲sIndex的變量，該變量指向當前選擇列表中所選選項的索引。（提示：使用此關鍵字來引用當前的選擇列表。） b）可以使用命令加載網頁 location.href = url; 其中，url是Web頁面的URL。使用選擇列表中選定選項的值作爲url的值，將此命令輸入到函數中。（提示：使用 SINDEX變量指向從當前選擇列表中選擇的選項。）

這裏是我的代碼：

<?xml version="1.0" encoding="UTF-8" ?> 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 

<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<!-- 
    New Perspectives on HTML, XHTML and DHTML 4th Edition 
    Tutorial 14 
    Case Problem 1 

    Monroe Public Library 
    Author: Collin Klopstein 
    Date: November 27, 2013 

    Filename:   mpl.htm 
    Supporting files: links.js, mplstyles.css. mpl.jpg 
--> 
    <title>Monroe Public Library List of Government Sites</title> 
    <link href="mplstyles.css" rel="stylesheet" type="text/css" /> 

    <script type="text/javascript"> 
    window.onload = init; 

    function init() { 
     var allSelect = document.getElementsByTagName("*"); 

     for (var i = 0; i < allSelect.length; i++) { 
      if (allSelect[i].classname == "optionLinks") allSelect.push(allSelect[i]) { 
      allSelect[i].onchange = loadLink; 
      } 
     } 
    } 

    function loadLink() { 
     var sIndex = this.selectedIndex; 
     location.href = this.options[sIndex].value; 
    } 
    </script> 

</head> 

<body> 
<p id="head"> 
    <img src="mpl.jpg" alt="Monroe Public Library" /> 
</p> 

<div id="links"> 
    <span>Quick Links</span> 
    <a href="#">Home Page</a> 
    <a href="#">Online Catalog</a> 
    <a href="#">Friends of MPL</a> 
    <a href="#">New Books and Other Good Reading</a> 
    <a href="#">Illinois Virtual Library</a> 
    <a href="#">Internet Public Library</a> 
    <a href="#">Services and Collection</a> 
    <a href="#">Adult Programs</a> 
    <a href="#">Teen Central</a> 
    <a href="#">Children's Room</a> 
</div> 

<div id="main"> 
<h2>Government Sites on the Web</h2> 

<p>Select a site from one of the drop-down lists below.</p> 
<table> 
    <tr><td>Executive Branch</td> 
     <td><select name="executive" id="executive" class="optionLinks"> 
      <option value="#">Select a Web site</option> 
      <option value="http://www.whitehouse.gov">The White House</option> 
      <option value="http://www.usda.gov">Department of Agriculture</option> 
      <option value="http://www.doc.gov">Department of Commerce</option> 
      <option value="http://www.defenselink.mil">Department of Defense</option> 
      <option value="http://www.ed.gov">Department of Education</option> 
      <option value="http://www.energy.gov">Department of Energy</option> 
      <option value="http://www.os.dhhs.gov">Department of Health and Human Services</option> 
      <option value="http://www.whitehouse.gov/homeland">Department of Homeland Security</option> 
      <option value="http://www.hud.gov">Department of Housing and Urban Development</option> 
      <option value="http://www.doi.gov">Department of the Interior</option> 
      <option value="http://www.usdoj.gov">Department of Justice</option> 
      <option value="http://www.dol.gov">Department of Labor</option> 
      <option value="http://www.state.gov">Department of State</option> 
      <option value="http://www.ustreas.gov">Department of the Treasury</option> 
      </select> 
     </td> 
    </tr> 
    <tr><td>Legislative Branch</td> 
     <td><select name="legislative" id="legislative" class="optionLinks"> 
      <option value="#">Select a Web site</option> 
      <option value="http://www.house.gov">House Web Site</option> 
      <option value="http://www.house.gov/house/MemberWWW.shtml">Representatives' Web Sites</option> 
      <option value="http://clerk.house.gov/">Clerk of the House</option> 
      <option value="http://www.gpoaccess.gov/cdirectory/index.html">Congressional Directory</option> 
      <option value="http://www.senate.gov">Senate Web Site</option> 
      <option value="http://www.senate.gov/general/contact_information/senators_cfm.cfm">Senators' Web Sites</option> 
      <option value="http://www.senate.gov/artandhistory/history/common/generic/Senate_Historical_Office.htm">Senate Historic Office</option> 
      <option value="http://www.cq.com">Congressional Quarterly</option> 
      <option value="http://www.loc.gov/">Library of Congress</option> 
      <option value="http://www.gao.gov/">Government Accountability Office</option> 
      <option value="http://www.cbo.gov/">Congressional Budget Office</option> 
      <option value="http://www.gpoaccess.gov/">Government Printing Office</option> 
      <option value="http://thomas.loc.gov/home/legbranch/otherleg.html#govpub">Government Records and Publications</option> 
      </select> 
     </td> 
    </tr> 
    <tr><td>Judicial Branch</td> 
     <td><select name="judicial" id="judicial" class="optionLinks"> 
      <option value="#">Select a Web site</option> 
      <option value="http://www.uscourts.gov">U.S. Courts</option> 
      <option value="http://www.uscourts.gov/supremecourt.html">U.S. Supreme Court</option> 
      <option value="http://www.uscourts.gov/courtsofappeals.html">U.S. Courts of Appeals</option> 
      <option value="http://www.uscourts.gov/districtcourts.html">U.S. District Courts</option> 
      </select> 
     </td> 
    </tr> 
    <tr><td>State Governments</td> 
     <td><select name="state" id="state" class="optionLinks"> 
      <option value="#">Select a Web site</option> 
      <option value="http://www.statelocalgov.net/index.cfm">State and Local Government on the Net</option> 
      <option value="http://www.loc.gov/global/state/al-gov.html">Alabama</option> 
      <option value="http://www.loc.gov/global/state/ak-gov.html">Alaska</option> 
      <option value="http://www.loc.gov/global/state/az-gov.html">Arizona</option> 
      <option value="http://www.loc.gov/global/state/ar-gov.html">Arkansas</option> 
      <option value="http://www.loc.gov/global/state/ca-gov.html">California</option> 
      <option value="http://www.loc.gov/global/state/co-gov.html">Colorado</option> 
      <option value="http://www.loc.gov/global/state/ct-gov.html">Connecticut</option> 
      <option value="http://www.loc.gov/global/state/de-gov.html">Delaware</option> 
      <option value="http://www.loc.gov/global/state/dc-gov.html">District of Columbia</option> 
      <option value="http://www.loc.gov/global/state/fl-gov.html">Florida</option> 
      <option value="http://www.loc.gov/global/state/ga-gov.html">Georgia</option> 
      <option value="http://www.loc.gov/global/state/hi-gov.html">Hawaii</option> 
      <option value="http://www.loc.gov/global/state/id-gov.html">Idaho</option> 
      <option value="http://www.loc.gov/global/state/il-gov.html">Illinois</option> 
      <option value="http://www.loc.gov/global/state/in-gov.html">Indiana</option> 
      <option value="http://www.loc.gov/global/state/ia-gov.html">Iowa</option> 
      <option value="http://www.loc.gov/global/state/ks-gov.html">Kansas</option> 
      <option value="http://www.loc.gov/global/state/ky-gov.html">Kentucky</option> 
      <option value="http://www.loc.gov/global/state/la-gov.html">Louisana</option> 
      <option value="http://www.loc.gov/global/state/me-gov.html">Maine</option> 
      <option value="http://www.loc.gov/global/state/md-gov.html">Maryland</option> 
      <option value="http://www.loc.gov/global/state/ma-gov.html">Massachusetts</option> 
      <option value="http://www.loc.gov/global/state/mi-gov.html">Michigan</option> 
      <option value="http://www.loc.gov/global/state/mn-gov.html">Minnesota</option> 
      <option value="http://www.loc.gov/global/state/ms-gov.html">Mississippi</option> 
      <option value="http://www.loc.gov/global/state/mo-gov.html">Missouri</option> 
      <option value="http://www.loc.gov/global/state/mn-gov.html">Montana</option> 
      <option value="http://www.loc.gov/global/state/ne-gov.html">Nebraska</option> 
      <option value="http://www.loc.gov/global/state/nv-gov.html">Nevada</option> 
      <option value="http://www.loc.gov/global/state/nh-gov.html">New Hampshire</option> 
      <option value="http://www.loc.gov/global/state/nj-gov.html">New Jersey</option> 
      <option value="http://www.loc.gov/global/state/nm-gov.html">New Mexico</option> 
      <option value="http://www.loc.gov/global/state/ny-gov.html">New York</option> 
      <option value="http://www.loc.gov/global/state/nc-gov.html">North Carolina</option> 
      <option value="http://www.loc.gov/global/state/nd-gov.html">North Dakota</option> 
      <option value="http://www.loc.gov/global/state/oh-gov.html">Ohio</option> 
      <option value="http://www.loc.gov/global/state/ok-gov.html">Oklahoma</option> 
      <option value="http://www.loc.gov/global/state/or-gov.html">Oregon</option> 
      <option value="http://www.loc.gov/global/state/pa-gov.html">Pennsylvania</option> 
      <option value="http://www.loc.gov/global/state/ri-gov.html">Rhode Island</option> 
      <option value="http://www.loc.gov/global/state/sc-gov.html">South Carolina</option> 
      <option value="http://www.loc.gov/global/state/sd-gov.html">South Dakota</option> 
      <option value="http://www.loc.gov/global/state/tn-gov.html">Tennessee</option> 
      <option value="http://www.loc.gov/global/state/tx-gov.html">Texas</option> 
      <option value="http://www.loc.gov/global/state/ut-gov.html">Utah</option> 
      <option value="http://www.loc.gov/global/state/vt-gov.html">Vermont</option> 
      <option value="http://www.loc.gov/global/state/va-gov.html">Virginia</option> 
      <option value="http://www.loc.gov/global/state/wa-gov.html">Washington</option> 
      <option value="http://www.loc.gov/global/state/wv-gov.html">West Virginia</option> 
      <option value="http://www.loc.gov/global/state/wi-gov.html">Wisconsin</option> 
      <option value="http://www.loc.gov/global/state/wy-gov.html">Wyoming</option> 
      </select> 
     </td> 
    </tr> 
</table> 
<address> 
    <b>Monroe Public Library</b> 
    580 Main Street, Monroe, OH &nbsp;&nbsp;45050 
    <b>Phone</b> (513) 555-0211 
    <b>Fax</b> (513) 555-0241 
</address> 
</div>  

</body> 
</html>

來源

2013-11-27 howdydoody

*家庭作業* – ElliotM

您的觀點是什麼，ElliotM？ – MultiplyByZer0

的說明不具體說了，你不能改寫loadLink()接受一個參數，所以這可能會激怒你的教授正確實施的想法。

這是我實現http://jsfiddle.net/fenderistic/9LK5C/

function init() { 
     var allSelect = document.getElementsByTagName("select"); 

     for (var i = 0; i < allSelect.length; i++) { 

     // allSelect.push(allSelect[i]) 
      allSelect[i].setAttribute("onChange","loadLink(this)"); 
     } 

    } 


loadLink = function(e) { 

    var sIndex = e.selectedIndex; 
    location.href = e.options[sIndex].value; 
}

標籤名稱的改變讓我刪除if聲明

而且不知道爲什麼你推到數組，所以我刪除了這一點。

來源

2013-11-27 19:44:36 ElliotM

謝謝ElliotM！我將標記名稱更改爲「select」，刪除了if語句和push方法，現在它正在運行。謝謝你的幫助！ – howdydoody

如果確實回答了您的問題，請選擇此爲答案。別客氣！ – ElliotM

我無法使用我的網頁瀏覽位於JScript中的選擇列表中的網址。

回答

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