js关于字符串连接错误！跪求指导啊！
严重: Servlet.service() for servlet jsp threw exception
java.lang.NumberFormatException: For input string: ""+k+""
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.valueOf(Unknown Source)
at org.apache.jasper.compiler.JspUtil.coerceToInt(JspUtil.java:765)
at org.apache.jasper.compiler.Generator$GenerateVisitor.convertString(Generator.java:3131)
at org.apache.jasper.compiler.Generator$GenerateVisitor.evaluateAttribute(Generator.java:2946)
at org.apache.jasper.compiler.Generator$GenerateVisitor.generateSetters(Generator.java:3051)
at org.apache.jasper.compiler.Generator$GenerateVisitor.generateCustomStart(Generator.java:2231)
at org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1746)
at org.apache.jasper.compiler.Node$CustomTag.accept(Node.java:1530)
at org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2361)
at org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2411)
at org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2417)
at org.apache.jasper.compiler.Node$Root.accept(Node.java:495)
at org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2361)
at org.apache.jasper.compiler.Generator.generate(Generator.java:3459)
at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:231)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:354)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:334)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:321)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:592)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:328)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)
<script type="text/javascript" language="javascript">
var flag=0;
var speed=5;
var MyMar=null;
var mousedown=false;
var scroll=null;
var i=1;
Direction='Left';
function out(){
flag=xold;
}
function over(){
}
var x=0, y=0, xold=0, yold=0, xdiff=0, ydiff=0;
function FindXY(loc) {
//document.getElementById("demo2").innerHTML=document.getElementById("demo1").innerHTML;
//window.alert(document.getElementById("demo").scrollLeft);
//window.alert(document.getElementById("demo1").offsetWidth);
//window.alert(5*i);
x = (document.layers) ? loc.pageX : event.clientX;
y = (document.layers) ? loc.pageY : event.clientY;
xdiff = x - xold;
ydiff = y - yold;
//if(document.getElementById("demo").scrollLeft==0){
//var str="<table border='0' align='center' cellpadding='0' cellspacing='0'><tr valign='top' ><c:forEach items='${requestScope.pro_list}' var='pro' begin='5' end='9'><td align='center' style='border:1px solid #FFFFFF;'><div><img src='${pro.product_pic}' class='listimage' ondblclick='javascript:detail('${pro.pro_no}')'></img><br>${pro.pro_no}</div></td></c:forEach></tr></table>";
//document.getElementById("demo2").innerHTML=str;
//}
if((xdiff<0)&&(document.getElementById("demo2").offsetWidth-document.getElementById("demo").scrollLeft<=0)){
document.getElementById("demo").scrollLeft=0;
document.getElementById("demo1").innerHTML=document.getElementById("demo2").innerHTML;
//window.alert(5*i);
var k=(5*i).toString();
var str="<table border='0' align='center' cellpadding='0' cellspacing='0'><tr valign='top' ><c:forEach items='${requestScope.pro_list}' var='pro' begin='"+k+"' end='"+(5*i+4).toString()+"'><td align='center' style='border:1px solid #FFFFFF;'><div><img src='${pro.product_pic}' class='listimage' ondblclick='javascript:detail('${pro.pro_no}')'></img><br>${pro.pro_no}</div></td></c:forEach></tr></table>";
document.getElementById("demo2").innerHTML=str;
}
if((xdiff>0)&&(document.getElementById("demo").scrollLeft<=0)){
document.getElementById("demo2").innerHTML=document.getElementById("demo1").innerHTML;
var str="<table border='0' align='center' cellpadding='0' cellspacing='0'><tr valign='top' ><c:forEach items='${requestScope.pro_list}' var='pro' begin='"+5*(i-1).toString()+"' end='"+(5*(i-1)+4).toString()+"'><td align='center' style='border:1px solid #FFFFFF;'><div><img src='${pro.product_pic}' class='listimage' ondblclick='javascript:detail('${pro.pro_no}')'></img><br>${pro.pro_no}</div></td></c:forEach></tr></table>";
document.getElementById("demo1").innerHTML=str;
document.getElementById("demo").scrollLeft=document.getElementById("demo2").offsetWidth;
}
if(flag==0){
//window.alert(xdiff);
document.getElementById("demo").scrollLeft=document.getElementById("demo").scrollLeft-xdiff;
//if(document.getElementById("demo").scrollLeft!=0)
//window.alert(document.getElementById("demo").scrollWidth);
//window.alert(document.getElementById("demo").scrollWidth+" "+document.getElementById("demo").offsetWidth);
}
//if(document.getElementById("demo1").offsetWidth-document.getElementById("demo").scrollLeft<=1000){
// var str="<table border='0' align='center' cellpadding='0' cellspacing='0'><tr valign='top' ><c:forEach items='${requestScope.pro_list}' var='pro' begin='0' end='4'><td align='center' style='border:1px solid #FFFFFF;'><div><img src='${pro.product_pic}' class='listimage' ondblclick='javascript:detail('${pro.pro_no}')'></img><br>${pro.pro_no}</div></td></c:forEach></tr></table>";
// document.getElementById("demo2").innerHTML=str;
//window.alert(document.getElementById("demo1").offsetWidth);
//window.alert(document.getElementById("demo").scrollWidth);
//}
xold = x;
yold = y;
flag=0;
}
</script>
[解决办法]
<c:forEach这些是服务器端标签，你放js里面怎么执行啊
[解决办法]
