删除特殊字符和限定用户输入长度的示例代码

/检查非法字符并检验字符长度 
function checkSpeChar(obj, byteLength, title) { 
var value = document.getElementById(obj).value; 
value = value.replace(/(^\s*)/g, "").replace(/(\s*$)/g, ""); 
var ret = (/[-|;|,|\/|\(|\)|\[|\]|\}|\{|%|@|\*|!|\']/.test(value)); 
var arr = ["@", "#", "$", "%", "^", "&", "*", "<", ">", "/", "\\", "\'", "'", ".", ":", "?", "[", "]", ";", "-", "、", "(", ")", "_", "\"", "~", "insert", "delete", "update", "select"]; 
value = value.toLowerCase(); 
for (var i = 0; i < arr.length; i++) { 
if (value.indexOf(arr[i].toLowerCase()) >= 0) { 
ret = true; 
} 
} 
if (ret == true) { 
top.LSAlert("内容中含非法字符，请重新输入！"); 
document.getElementById(obj).value = ''; 
return; 
} 
limitLength(value, byteLength, title, obj); 
} 
//验证输入字符长度 
function limitLength(value, byteLength, title, attribute) { 
value = value.replace(/\r/g, " ").replace(/\n/g, " "); //回车换行分别替换两个空格 
var newvalue = value.replace(/[^\x00-\xff]/g, "***"); 
var length = newvalue.length; 
//当填写的字节数小于设置的字节数 
if (length * 1 <= byteLength * 1) { 
return; 
} 
var limitDate = newvalue.substr(0, byteLength); 
var count = 0; 
var limitvalue = ""; 
for (var i = 0; i < limitDate.length; i++) { 
var flat = limitDate.substr(i, 1); 
if (flat == "*") { 
count++; 
} 
} 
var size = 0; 
var istar = newvalue.substr(byteLength * 1 - 1, 1); //校验点是否为“×” 
//if 基点是×; 
if (count % 3 == 0) { 
size = count / 3 + (byteLength * 1 - count); 
limitvalue = value.substr(0, size); 
} 
else if (count % 3 == 1) { 
size = (count - 1) / 3 + (byteLength * 1 - count); 
limitvalue = value.substr(0, size); 
} 
else if (count % 3 == 2) { 
size = (count - 2) / 3 + (byteLength * 1 - count); 
limitvalue = value.substr(0, size); 
} 
//top.LSAlert(title + "最大输入" + byteLength + "个字节！"); 
document.getElementById(attribute).value = limitvalue; 
return; 
}