用 onerror 获取错误信息

这个东西是在线写 js 脚本的时候，用来即时查错的东西！

也就是，当发现所编写的脚本有问题的时候会有相应的提示，并且在源代码框中高亮标示出错行，方便除错

〈HTML>
〈HEAD>
〈TITLE>Debug Textarea〈/TITLE>
〈meta http-equiv='Content-Type' content='text/html; charset=gb2312'>
〈/HEAD>
〈style>
* {
font-size: 12px
}
body {
margin: 10px; padding: 0px
}
table.list{
cursor: default;
border:1px solid #cccccc
background-color: #cccccc;
border-collapse: collapse;
border-Color: #cccccc;
}
〈/style>
〈script language="javascript">
// Coded by windy_sk 〈[e-mail]> 20040205

function reportError(msg,url,line) {
var str = "You have found an error as below: \n\n";
str += "Err: " + msg + " on line: " + line;
alert(str);
return true;
}

window.onerror = reportError;


document.onkeydown = function() {
if(event.ctrlKey){
  switch(event.keyCode) {
   case 82: //r
    runcode();
    break;
   case 83: //s
    savecode();
    break;
   case 71: //g
    goto(prompt('Please input the line number', '1'));
    break;
   case 65: //a
    document.execCommand("SelectAll");
    break;
   case 67: //c
    document.execCommand("Copy");
    break;
   case 88: //x
    document.execCommand("Cut");
    break;
   case 86: //v
    document.execCommand("Paste");
    break;
   case 90: //z
    document.execCommand("Undo");
    break;
   case 89: //y
    document.execCommand("Redo");
    break;
   default:
    break;
  }
  event.keyCode = 0;
  event.returnValue = false;
}
return;
}


function show_ln(){
var txt_ln  = document.getElementById('txt_ln');
var txt_main  = document.getElementById('txt_main');
txt_ln.scrollTop = txt_main.scrollTop;
while(txt_ln.scrollTop != txt_main.scrollTop) {
  txt_ln.value += (i++) + '\n';
  txt_ln.scrollTop = txt_main.scrollTop;
}
return;
}


function editTab(){
var code, sel, tmp, r;
event.returnValue = false;
sel =event.srcElement.document.selection.createRange();
r = event.srcElement.createTextRange();

switch (event.keyCode){
  case (8) :
   if (!(sel.getClientRects().length > 1)){
    event.returnValue = true;
    return;
   }
   code = sel.text;
   tmp = sel.duplicate();
   tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top);
   if(sel.parentElement() != tmp.parentElement()) return;;
   sel.setEndPoint('startToStart', tmp);
   sel.text = sel.text.replace(/^\t/gm, '');
   code = code.replace(/^\t/gm, '').replace(/\r\n/g, '\r');
   r.findText(code);
   r.select();
   break;
  case (9) :
   if (sel.getClientRects().length > 1){
    code = sel.text;
    tmp = sel.duplicate();
    tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top);
    if(sel.parentElement() != tmp.parentElement()) return;
    sel.setEndPoint('startToStart', tmp);
    sel.text = '\t'+sel.text.replace(/\r\n/g, '\r\t');
    code = code.replace(/\r\n/g, '\r\t');
    r.findText(code);
    r.select();
   }else{
    sel.text = '\t';
    sel.select();
   }
   break
  case (13) :
   tmp = sel.duplicate();
   tmp.moveToPoint(r.getBoundingClientRect().left, sel.getClientRects()[0].top);
   if(sel.parentElement() != tmp.parentElement()) return;
   tmp.setEndPoint('endToEnd', sel);
   sel.text = '\r\n' + tmp.text.replace(tmp.text.replace(/^[\t ]+/g, ""),"");
   sel.select();
   break;
  default  :
   event.returnValue = true;
   break;
}
return;
}


function runcode() {
var str = document.getElementById("txt_main").value;
var code_win = window.open('about:blank');
code_win.document.open();
code_win.document.writeln("〈script>");
code_win.document.writeln("function reportError(msg,url,line){\nline-=14;\nvar str='You have found an error as below: \\n\\n';\nstr+='Err: '+msg+' on line: '+(line);\nalert(str);\nopener.goto(line);\nopener.focus();\nwindow.onerror=null;\nsetTimeout('self.close()',10);\nreturn true;\n}");
code_win.document.writeln("window.onerror = reportError;");
code_win.document.writeln("〈\/script>");
code_win.document.writeln(str);
code_win.document.close();
return;
}


function savecode() {
var str = document.getElementById("txt_main").value;
var code_win = window.open('about:blank','_blank','top=10000');
code_win.document.open();
code_win.document.writeln(str);
code_win.document.close();
code_win.document.execCommand('saveas','','code.html');
code_win.close();
return;
}


function goto(ln) {
if(!/^\d+$/.test(ln) || ln==0) return;
var obj = document.getElementById("txt_main");
var rng = obj.createTextRange();
var arr = obj.value.split(/\n/);
if(ln>arr.length) ln = arr.length;
var str_tmp = "";
for(var i=0; i〈ln-1; i++) {
  str_tmp += arr[i];
}
rng.moveStart('character',str_tmp.length);
str_tmp = "";
for(i=ln; i〈arr.length; i++) {
  str_tmp += arr[i];
}
rng.moveEnd('character',-str_tmp.length);
rng.select();
return;
}

window.onload = function() {document.getElementById("txt_main").value = "〈script>\nalert(')\n〈\/script>";}
〈/script>
〈BODY>
〈table width='600' class='list' border='1' bgcolor='#eeeeee' bordercolorlight='#000000' bordercolordark='#FFFFFF' cellpadding='0' cellspacing='0'>
  〈tr bgcolor='#cccccc'>
    〈td colspan='2' height='20' align='center'>〈b>Debug Textarea〈/b>〈/td>
  〈/tr>
  〈tr>
    〈td colspan='2'>
        〈table width='95%' border='0' align='center' >
   〈tr>
     〈td align='center'>〈br />
       〈textarea id='txt_ln' name='content' rows='10' style='width:40px;overflow:hidden;height:200px;border-right:0px;text-align:right;line-height:14px' onselectstart='this.nextSibling.focus();return false' readonly>〈/textarea>〈textarea id='txt_main' name='content' rows='10' cols='80' onkeydown='editTab()' onkeyup='show_ln()' onscroll='show_ln()' wrap='off' style='overflow:auto;height:200px;padding-left:5px;border-left:0px;line-height:14px'>〈/textarea>
       〈script>for(var i=1; i〈=20; i++) document.getElementById('txt_ln').value += i + '\n';〈/script>
     〈/td>
   〈/tr>
          〈tr>
            〈td align='center'>〈br />
              〈input type='button' value=' 运 行 ' onclick='runcode()' accesskey='r'> 
              〈input type='button' value=' 保 存 ' onclick='savecode()' accesskey='s'> 
              〈input type='button' value=' 跳 转 ' onclick="goto(prompt('Please input the line number', '1'))"  accesskey='g'> 
            〈/td>
          〈/tr>
        〈/table>
    〈/td>
  〈/tr>
〈/table>
〈/BODY>
〈/HTML>