如何用javascript删除或禁用同页面的另一个javascript
已知在一个html中有若干javascript，现要求用某个javascript删除最后一个javascript，实例如下
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=gb2312" /><title>无标题文档</title></head><body><script type="text/javascript">document.write("js1\n");</script><script type="text/javascript">document.write("js2\n");</script><script type="text/javascript">document.write("js3\n");</script><script type="text/javascript">document.write("js4\n");</script><script type="text/javascript">/*删除最后一个javascript，使之不执行，页面上不会出现 js5 */</script><script type="text/javascript" id="target">document.write("js5\n");</script></body></html><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=gb2312" /><title>无标题文档</title></head><body><script type="text/javascript">document.write("js1\n");</script><script type="text/javascript">document.write("js2\n");</script><script type="text/javascript">document.write("js3\n");</script><script type="text/javascript">document.write("js4\n");</script><script type="text/javascript">//实现的原理是重写目标代码段里调用的第一个函数，从里面throw一个异常出来，终结掉整个代码段的执行//首先保存write函数，以便执行完以后恢复。如果你不需要恢复，那么就不需要保存var temp=document.write;document.write=function(){throw 1;};</script><script type="text/javascript" id="target">document.write("js5\n");alert(1);</script><script type="text/javascript">//恢复write函数，以便其他调用document.write=temp;</script><script type="text/javascript">document.write("js6\n");</script></body></html>