如何通过使用javascript和jsp删除链接删除图像？

Question

我正在尝试删除图片文件并替换新图片...但我没有得到正确并面临如此多的错误..请纠正它并给我解决方案也..请纠正我的错误

// JSP代码

 <tr id="docFileUpload_<%=AppConstants.FALSE%>">
 <c:set var="answerSize" value="${fn:length(editForm.answer[0])}"/>

    <td class="data">A. 
    <c:choose>
    <c:when test="${editForm.answer[0]!=null}">
    <form:input path="answer[0]" size="50" maxlength="250" id="remove_image"/><br>&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;<strong><fmt:message key="label.or"/></strong><br>
    <input type="file" name="answerImage[0]"/>
    </c:when>
    <c:otherwise>
    <img alt="" src="${answerPath0}">
    </c:otherwise>

    </c:choose>

    <c:out value="${editForm.answerImage[0]}"/>&nbsp;[<a href="javascript:processRemoveDocFile();"><fmt:message key="link.removeFile"/></a>]
        </td>
        <td class="data"><form:checkbox path="flag[0]" value="true"/>           

</tr>
<tr id="docFileUpload_<%=AppConstants.TRUE%>">
<td class="data" >
            <input type="file" name="answerImage[0]"/>
    </td>   
        <td class="data"><form:checkbox path="flag[0]" value="true"/>       
</tr>

// Java脚本代码

<script type="text/javascript">

    var maxLenArray = new Array('comments||500');
    initMaxLengthAttributes(maxLenArray);

    function init()
    {
        //var maxLenArray = new Array('document_descId||500', 'document_commentsId||500');          
        //initMaxLengthAttributes(maxLenArray);

        processDocFileUploadOnLoad();   
        processTempFileUploadOnLoad();  
    }

</script>

<script>
    function processDocFileUploadOnLoad()
    {

        // get reference to form
        var theForm = YAHOO.util.Dom.get('editForm');
        // get reference to radio buttons
        var docFileUpdateRef = theForm.document_file_update;        
        processDocFileUpload(docFileUpdateRef); 
    }

    function processDocFileUpload(fileUpdateRef)
    {

        var fileUpdateValue = fileUpdateRef.value;

        var selectedSectionId = 'docFileUpload_' + fileUpdateValue;
        var trueSectionId = 'docFileUpload_' + '<%=AppConstants.TRUE%>';
        var falseSectionId = 'docFileUpload_' + '<%=AppConstants.FALSE%>';

            // show old input, hide current input
        if(fileUpdateValue == '<%=AppConstants.TRUE%>')
        {
            switchSections(selectedSectionId, new Array(falseSectionId));
        }
        // show current input, hide old input
        else if(fileUpdateValue == '<%=AppConstants.FALSE%>')
        {
            switchSections(selectedSectionId, new Array(trueSectionId));
        }

    }

    function processRemoveDocFile()
    {
        // get reference to form
        var theForm = YAHOO.util.Dom.get('editForm');

        var docFileUpdateRef = theForm.document_file_update;
        docFileUpdateRef.value = true;

        processDocFileUpload(docFileUpdateRef);
    }
</script>

<script>
    YAHOO.util.Event.onDOMReady(init);
</script>