Why do some web page style attributes need a colon ":" and some do not?

Colonized , After the description is a variable or expression ; The literal value of the corresponding string is followed by no colon ！

Example ：

<el-radio-group v-model="handle">

<el-radio :label="true"> open </el-radio>

<el-radio :label="false"> close </el-radio>

</el-radio-group>

Output ：true or false The value is Boolean type

---

Example ：

<el-radio-group v-model="handle">

<el-radio label="true"> open </el-radio>

<el-radio label="false"> close </el-radio>

</el-radio-group>

Output ：”true" or “false” The value is String type