function t1(){
  var cont = document.getElementById('cont');
  var cv = cont.value;
  var reg = /hi/;//仅仅是看字符串中有没有hi
  alert(reg.test(cv));//满足 返回true  不满足 返回false
}
function t2(){
  var cont = document.getElementById('cont');
  var cv = cont.value;
  //var reg = /\bhi.+/;// 错误1 匹配hi开头的单词
  ////var reg = /\bhi\w+/;// 错误2
  var reg = /\bhi\w*/; 
  alert(reg.exec(cv));//exec返回一个对象  没找到返回none
}
function t3(){
  var cont = document.getElementById('cont');
  var cv = cont.value;
  var reg = /\bhi/;//正则测试hi开头的单词但不是hi
  alert(reg.exec(cv));//exec返回一个对象  没找到返回none
} 
function t4(){
  var cont = document.getElementById('cont');
  var cv = cont.value;
  var reg = /\b[\w]+ing\b/;//*表示匹配0-无穷  +表示匹配1-无穷
  alert(reg.exec(cv));
} 
function t5(){
  var cont = document.getElementById('cont');
  var cv = cont.value;
  var reg = /\bun[\w]+\b/;//匹配un前缀的反义词
  alert(reg.exec(cv));
}
function t6(){
  var cont = document.getElementById('cont');
  var cv = cont.value;
  var reg = /\Bhi\B/;//匹配单词中间的hi部分
  alert(reg.exec(cv));
}
function t7(){
  var cont = document.getElementById('cont');
  var cv = cont.value;
  var reg = /^lisi$/;//匹配输入的名字是不是lisi
  alert(reg.exec(cv));
}