document.all.kind.options[1].selected = "false";这里select 的selected属性在脚本里设置时必须是布尔型的，你弄了个字符串，当然是true了 DOM参考Syntax HTML：<OPTION SELECTED ... > Scripting：OPTION.selected [ = bSelected ] Possible Values bSelected Boolean that specifies or receives one of the following values. false(Default). Item is not selected as the default. true Item is selected as the default. The property is read/write. The property has a default value of false.Expressions can be used in place of the preceding value(s), as of Microsoft® Internet Explorer 5. For more information, see About Dynamic Properties.
DOM参考Syntax HTML：<OPTION SELECTED ... >
Scripting：OPTION.selected [ = bSelected ] Possible Values bSelected Boolean that specifies or receives one of the following values.
false(Default). Item is not selected as the default.
true Item is selected as the default.
The property is read/write. The property has a default value of false.Expressions can be used in place of the preceding value(s), as of Microsoft® Internet Explorer 5. For more information, see About Dynamic Properties.