下面是Bootstrap使用的代码。颜色略有不同,但概念相同。这是如果您使用LESS来编译CSS:
// Form control focus state
//
// Generate a customized focus state and for any input with the specified color,
// which defaults to the `@input-focus-border` variable.
//
// We highly encourage you to not customize the default value, but instead use
// this to tweak colors on an as-needed basis. This aesthetic change is based on
// WebKit's default styles, but applicable to a wider range of browsers. Its
// usability and accessibility should be taken into account with any change.
//
// Example usage: change the default blue border and shadow to white for better
// contrast against a dark gray background.
.form-control-focus(@color: @input-border-focus) {
@color-rgba: rgba(red(@color), green(@color), blue(@color), .6);
&:focus {
border-color: @color;
outline: 0;
.box-shadow(~"inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px @{color-rgba}");
}
}
如果您不使用LESS,则为编译后的版本:
.form-control:focus {
border-color: #66afe9;
outline: 0;
-webkit-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
}