JS验证字符串功能

js 验证字符串功能实例代码如下所示：

//去除空格 
function jstrim(value) { 
  var reg = /^\s$/; 
  if (!value) return ""; 
  if (value.length == 0) 
    return value; 
  else { 
    var lp, rp; 
    lp = 0; rp = value.length - 1; 
    while ((value.charat(lp) == " " || (value.charcodeat(lp) < 128 ? (reg.test(value.charat(lp)) == false ? true : false) : false) || value.charat(rp) == " " || (value.charcodeat(rp) < 128 ? (reg.test(value.charat(rp)) == false ? true : false) : false)) && rp >= lp) { 
      if (value.charat(lp) == " " || value.charcodeat(lp) < 128 ? (reg.test(value.charat(lp)) == false ? true : false) : false) 
        lp++; 
      if (value.charat(rp) == " " || value.charcodeat(rp) < 128 ? (reg.test(value.charat(rp)) == false ? true : false) : false) 
        rp--; 
    } 
    if (lp > rp) 
      return ""; 
    else 
      return (value.substring(lp, rp + 1)); 
  } 
} 
//字符串长度 
function strlength(s) { 
  var s_length = s.length; 
  return s_length; 
} 
//手机号码验证函数 
string.prototype.trim = function() { 
  var m = this.match(/^\s*(\s+(\s+\s+)*)\s*$/); 
  return (m == null) ? "" : m[1]; 
} 
string.prototype.ismobile = function() { 
  return (/^(?:13\d|15\d|18\d|19\d|17\d|14\d)-?\d{5}(\d{3}|\*{3})$/.test(this.trim())); 
} 
//*判别电话号码，手机号是否有效 
//*返回 true:false 
//*/ 
function checkphone(phone)   
{   
//验证电话号码手机号码，包含153，159号段   
if (phone==""){   
alert("电话号码不能为空！");    
return false;   
}   
if (phone != ""){    
var p1 = /^(([0\+]\d{2,3}-)?(0\d{2,3})-)?(\d{7,8})(-(\d{3,}))?$/;   
var me = false;   
if (p1.test(phone)) me=true;   
if (!me){     
//alert('对不起，您输入的电话号码有错误。区号和电话号码之间请用-分割');    
return false;   
}   
}   
return true;   
}   
//邮箱地址验证函数 
function checkmail(mail) { 
//  var strr; 
//  re = /(\w+@\w+\.\w+)(\.{0,1}\w*)(\.{0,1}\w*)/i; 
//  re.exec(mail); 
//  if (regexp.$3 != "" && regexp.$3 != "." && regexp.$2 != ".") 
//    strr = regexp.$1 + regexp.$2 + regexp.$3 
//  else { 
//    if (regexp.$2 != "" && regexp.$2 != ".") 
//      strr = regexp.$1 + regexp.$2 
//    else 
//      strr = regexp.$1 
//  } 
//  if (strr != mail) { return false } else { return true } 
  //  return true; 
  var remail = /^([a-za-z0-9_\.\-])+\@(([a-za-z0-9\-])+\.)+([a-za-z0-9]{2,4})+$/; 
  return mail.match(remail); 
} 
//判断数字 
function checknumber(n) { 
  var checkok = "0123456789-."; 
  var allvalid = true; 
  var decpoints = 0; 
  var allnum = ""; 
  for (i = 0; i < n.length; i++) { 
    ch = n.charat(i); 
    for (j = 0; j < checkok.length; j++) 
      if (ch == checkok.charat(j)) 
      break; 
    if (j == checkok.length) { 
      allvalid = false; 
      break; 
    } 
    if (ch == ".") { 
      allnum += "."; 
      decpoints++; 
    } 
    else 
      allnum += ch; 
  } 
  if (!allvalid) 
    return false; 
  if (decpoints > 1) 
    return false; 
  return true; 
} 
//判断数字 
function checkn(n) { 
  var checkok = "0123456789"; 
  var allvalid = true; 
  var decpoints = 0; 
  var allnum = ""; 
  for (i = 0; i < n.length; i++) { 
    ch = n.charat(i); 
    for (j = 0; j < checkok.length; j++) 
      if (ch == checkok.charat(j)) 
      break; 
    if (j == checkok.length) { 
      allvalid = false; 
      break; 
    } 
    if (ch == ".") { 
      allnum += "."; 
      decpoints++; 
    } 
    else 
      allnum += ch; 
  } 
  if (!allvalid) 
    return false; 
  if (decpoints > 1) 
    return false; 
  return true; 
} 
var g_miny = 1601; 
var g_maxy = 4500; 
var rgmc = new array(12); 
rgmc[0] = 31; rgmc[1] = 28; rgmc[2] = 31; rgmc[3] = 30; rgmc[4] = 31; rgmc[5] = 30; rgmc[6] = 31; rgmc[7] = 31; rgmc[8] = 30; rgmc[9] = 31; rgmc[10] = 30; rgmc[11] = 31; 
function isdigit(c) { 
  return (c >= '0' && c <= '9'); 
} 
function getmonthcount(m, y) { 
  var c = rgmc[m - 1]; 
  if ((2 == m) && isleapyear(y)) c++; 
  return c; 
} 
function atoi(s) { 
  var t = 0; 
  for (var i = 0; i < s.length; i++) { 
    var c = s.charat(i); 
    if (!isdigit(c)) return t; 
    else t = t * 10 + (c - '0'); 
  } 
  return t; 
} 
//判断日期 
function checkdate(t) { 
  var l = t.length; 
  if (0 == l) return false; 
  var csp = '\0'; 
  var ssp1 = ''; 
  var ssp2 = ''; 
  for (var i = 0; i < t.length; i++) { 
    var c = t.charat(i); 
    if (c == ' ' || isdigit(c)) continue; 
    else if (csp == '\0' && (c == '/' || c == '-' || c == '.')) { 
      csp = c; 
      ssp1 = t.substring(i + 1, l); 
    } 
    else if (c == csp) ssp2 = t.substring(i + 1, l); 
    else if (c != csp) return false; 
  } 
  if (0 == ssp1.length) return false; 
  var m; 
  var d; 
  var y; 
  if (0 == ssp2.length) return false; 
  m = atoi(ssp1); 
  d = atoi(ssp2); 
  y = atoi(t); 
  if (y < 100) { 
    y = 1900 + y; 
    while (y < g_ylow) y = y + 100; 
  } 
  if (y < g_miny || y > g_maxy || m < 1 || m > 12) return false; 
  if (d < 1 || d > getmonthcount(m, y)) return false; 
  g_month = m; 
  g_day = d; 
  g_year = y; 
  return true; 
} 
//验证字符串必须为数字字母组合 
function isnumandstr(elem){ 
    var str = elem.value;  
   var regexpuperstr=/[a-z]+/; 
   var reexplowerstr=/[a-z]+/; 
   var regexpnum=/\d+/; 
   var uperstrflag = regexpuperstr.test(str); 
   var lowerstrflag = reexplowerstr.test(str); 
   var numflag = regexpnum.test(str); 
   if((uperstrflag&&lowerstrflag)||(lowerstrflag&&numflag)||(uperstrflag&&numflag)) 
     return true; 
   else 
    return false; 
} 
//验证字符串必须为数字跟字母的组合   
function checkpsw(str) { 
  if (str != "") { 
    var p1 = /(?!^[0-9]*$)(?!^[a-za-z]*$)^([a-za-z0-9]{2,})$/; 
    var me = false; 
    if (p1.test(str)) me = true; 
    if (!me) { 
      return false; 
    } 
  } 
  return true; 
} 
//验证字符串必须为数字跟字母的组合   
function checklen(str) { 
  if (str.length < 8 ) { 
      return false; 
    } 
  return true; 
} 
//单价 
function isprice(v) { 
  var mreg = /^[0-9]{1,10}(\.[0-9]{1,3})?$/; 
  if (mreg.test(v)) { 
    return true; 
  } 
  else { 
    return false; 
  } 
} 

以上所述是小编给大家介绍的js验证字符串功能，希望对大家有所帮助