很实用的js限制不让输入其他字符，只让输入数字和 js生成UUID

onkeyup="this.value=this.value.replace(/\D/g,‘‘)"

 1 var createUUID = (function (uuidRegEx, uuidReplacer) { 
 2      return function () { 
 3          return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(uuidRegEx, uuidReplacer).toUpperCase(); 
 4      }; 
 5  })(/[xy]/g, function (c) { 
 6      var r = Math.random() * 16 | 0, 
 7          v = c == "x" ? r : (r & 3 | 8); 
 8      return v.toString(16); 
 9  }); 
10  alert(createUUID());