getCurrentScript的改进

第一版

function getCurrentScript(){
    if(DOC.currentScript){
        return DOC.currentScript.src
    }
    var nodes = head.getElementsByTagName("script")//只在head标签中寻找
    for (var i = 0, node; node = nodes[i++];) {
        if (  node.readyState === "interactive") {
            return  node.className = node.src;
        }
    }
}

第二版

增加对firefox4-与chrome4+的支持

function getCurrentScript() {
      //取得正在解析的script节点
      if(DOC.currentScript) { //firefox 4+
          return DOC.currentScript.src;
      }
      var stack, e, nodes = head.getElementsByTagName("script"); //只在head标签中寻找
      //  参考 https://github.com/samyk/jiagra/blob/master/jiagra.js
      try {
          a.b.c(); //强制报错,以便捕获e.stack
      } catch(e) {
          stack = e.stack;
      }
      if(stack) {
          // chrome IE10使用 at, firefox opera 使用 @
          e = stack.indexOf(' at ') !== -1 ? ' at ' : '@';
          while(stack.indexOf(e) !== -1) {
              stack = stack.substring(stack.indexOf(e) + e.length);
          }
          return stack.replace(/:\d+:\d+$/ig, "");
      }
      for(i = 0; node = nodes[i++];) {
          if( node.readyState === "interactive") {
              return node.className = node.src;
          }
      }
  }

第三版

有的e.stack最后只有行号没有出错位置，导致正则取值失败，fix bug

function getCurrentScript() {
       //取得正在解析的script节点
       if(DOC.currentScript) { //firefox 4+
           return DOC.currentScript.src;
       }
       //  参考 https://github.com/samyk/jiagra/blob/master/jiagra.js
       var stack, e, i, node;
       try {
           a.b.c(); //强制报错,以便捕获e.stack
       } catch(e) {
           stack = e.stack;
       }
       if(stack) {
           // chrome IE10使用 at, firefox opera 使用 @
           e = stack.indexOf(' at ') !== -1 ? ' at ' : '@';
           i = stack.lastIndexOf(e);
           var a = stack.slice(i+e.length).replace(/\s\s*$/,"").replace(/(:\d+)?:\d+$/i,"");
           return a
       }
       var nodes = head.getElementsByTagName("script"); //只在head标签中寻找
       for(i = 0; node = nodes[i++];) {
           if( node.readyState === "interactive") {
               return node.className = node.src;
           }
       }
   }

第四版

IE10最后一行与其他浏览器不同，需要转换思路去掉杂质

function getCurrentScript() {
    //取得正在解析的script节点
    if(DOC.currentScript) { //firefox 4+
        return DOC.currentScript.src;
    }
    // 参考 https://github.com/samyk/jiagra/blob/master/jiagra.js
    var stack;
    try {
        a.b.c(); //强制报错,以便捕获e.stack
    } catch(e) {//safari的错误对象只有line,sourceId,sourceURL
        stack = e.stack;
        if(!stack && window.opera){
            //opera 9没有e.stack,但有e.Backtrace,但不能直接取得,需要对e对象转字符串进行抽取
            stack = (String(e).match(/of linked script \S+/g) || []).join(" ");
        }
    }
    if(stack) {
        /**e.stack最后一行在所有支持的浏览器大致如下:
        *chrome23:
        * at http://113.93.50.63/data.js:4:1
        *firefox17:
        *@http://113.93.50.63/query.js:4
        *opera12:
        *@http://113.93.50.63/data.js:4
        *IE10:
        *  at Global code (http://113.93.50.63/data.js:4:1)
        */
        stack = stack.split( /[@ ]/g).pop();//取得最后一行,最后一个空格或@之后的部分
        stack = stack[0] == "(" ? stack.slice(1,-1) : stack;
        return stack.replace(/(:\d+)?:\d+$/i, "");//去掉行号与或许存在的出错字符起始位置
    }
    var nodes = head.getElementsByTagName("script"); //只在head标签中寻找
    for(var i = 0, node; node = nodes[i++];) {
        if(node.readyState === "interactive") {
            return node.className = node.src;
        }
    }
}