代码如下：
<SCRIPT LANGUAGE="JavaScript"> <!-- Begin var mikExp = /[$\\@\\\#%\^\&\*\(\)\[\]\+\_\{\}\`\~\=\|]/; function dodacheck(val) { var strPass = val.value; var strLength = strPass.length; var lchar = val.value.charAt((strLength) - 1); if(lchar.search(mikExp) != -1) { var tst = val.value.substring(0, (strLength) - 1); val.value = tst; } } function doanothercheck(form) { if(form.value.length < 1) { alert("Please enter something."); return false; } if(form.value.search(mikExp) == -1) { alert("格式正确"); return false; } else { alert("对不起, 下列字符不能输入\n\r\n\r@ $ % ^ & * # ( ) [ ] \\ { + } ` ~ = | \n\r\n\请重输!\n"); form.select(); form.focus(); return false; } alert("格式正确"); return false; } // End --> </script> <form name=xyz onSubmit="return doanothercheck(this.txtTerm);"> <input type="text" name="txtTerm" size="35" maxlength="50" value="" onKeyUp="javascript:dodacheck(xyz.txtTerm);"> <br> <input type=submit value=Check> </form>