new RegExp()用法

    var str1 = new RegExp('e')
    document.write(str1.exec('hello'))

    var a = /678/
    b = /678/
    console.log(a);
    console.log(b);
    console.log(str1);
    console.log(str1.exec('hello'))
    console.log(a == b);   //false
    console.log(a === b);  //false