将’event.target.id’作为String

以下脚本返回错误：

"Uncaught TypeError: Object Reg_8712 has no method 'indexof' 

Reg_8712是解雇事件的单选按钮ID。

剧本：

 $("input:radio").change(function (event) { alert(event.target.id); // this works! it returns it as string. var eti = event.target.id; // 'eti' gets the object and not the string. var n = eti.indexof("_"); // error! cannot indexof ('eti' is an object and not string) var fid = eti.substring(n); 

如何将’eti’作为字符串？

Answer 1

如果某些东西确实不是字符串，最简单的转换方法是使用通用的.toString()方法：

 var eti = event.target.id.toString(); var n = eti.indexOf("_"); 

简单的测试用例来certificate这一点。

Answer 2

indexOf语法

string.indexOf(searchValue[, fromIndex])

  alert(event.target.id); // this works! it returns it as string. var eti = event.target.id.toString(); // 'eti' gets the object and not the string. var n = eti.indexOf("_"); // error! cannot indexof ('eti' is an object and not string) var fid = eti.substring(n); 

参考： https ： //developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf