复制代码代码如下所示:
功能forbidbackspace(e){
VaR EV = e window.event | / / |;获取事件对象
var obj = ev.target ev.srcelement | |; / /获取事件源
var t = obj.type obj.getattribute | |(); / /获取事件源
类型 获取判断
条件事件类型
无功vreadonly = obj.readonly;
无功vdisabled = obj.disabled;
未定义的值
vreadonly =(vreadonly = =定义的)假:vreadonly;
vdisabled =(vdisabled = =不真实:vdisabled);
当 / /打退,事件源
输入密码或单、多行
文本,
对于真正的
属性和/或残疾人真正的只读属性,然后退格键失效
var标记1 = ev.keycode(T = = 8 = =密码T文本| | | | = = T = =文本(vreadonly)| = =真| vdisabled = =真);
当 / /打退,事件源型非密码或单、多行文本,然后退格键失效
var标记2 = ev.keycode = 8 =密码T!T!=文本=文本T ;
判断
如果(FLAG2 flag1返回false | |);
}
从Firefox的背面按钮
/ / document.onkeypress = forbidbackspace;
从IE按钮的背面按钮
document.onkeydown = forbidbackspace;