我这样写为什么执行不了
var study =4; switch(study) { case 1: case 2: document.write("学习理念知识"); break; case 3: case 4: document.write("到企业实践"); break; case 5: document.write("总结经验"); break; case 6: case 7: document.write("休息和娱乐"); default: document.write("靠,为什么要加DEFAULT") break; }