07-String的扩展方法

一、模板字符串

    <div></div>
    <script>
        let age = 20
        let name = '张三'
        let person = `${name}的年龄为${age}`
        console.log(person);

        var divContent = document.querySelector('div')

        let obj = {
                name: 'hzp',
                age: 19
            }
            //模板字符串可以换行
        let html = `
        <div> 
            <span>${obj.name}</span>
            <span>${obj.age}</span>
        </div>
        `
        console.log(html);
        divContent.innerHTML = html

        const fn = () => {
            return 666
        }
        let ht = `fn()返回值为${fn()}`
        console.log(ht);
    </script>

二、startsWith和endsWith

    <script>
        let str = 'Hello World!'
        let flag = str.startsWith('Hello') //判断是否以Hello开头 返回布尔值
        let flag2 = str.startsWith('Helo') //判断是否以Hello开头 返回布尔值
        console.log(flag);
        console.log(flag2);
        let flag3 = str.endsWith('!') //判断是否以Hello开头 返回布尔值
        console.log(flag3);
    </script>

三、repeat()

    <script>
        //repeat(n) 将原字符串重复n次 返回一个新字符串
        let str = 'hzp'
        let str1 = str.repeat(2)
        console.log(str1);
    </script>