限制复选框最多选择项的实现代码

checkbox.onclick = function(){ //代码块}

if(chckbox.checked){ //代码块}

< input type= "checkbox" name= "sport"/>篮球<br />< input type= "checkbox" name= "sport"/>足球<br />< input type= "checkbox" name= "sport"/>排球<br />< input type= "checkbox" name= "sport"/>羽毛球<br/>< input type= "checkbox" name= "sport"/>乒乓球<br/>< p>最多选择三项</p>

var sportSelect = document.getElementsByName('sport' ),              maxNums   = 3;           for(var i in sportSelect){              sportSelect[i]. onclick = function (){                 var _sportSelect = document.getElementsByName('sport' ),                   cNums      = 0;                 for(var i in _sportSelect){                   if(i == 'length') break ;                   if(_sportSelect[i].checked){                      cNums ++;                   }                }                 if(cNums > maxNums){                   this.checked = false;                    alert('最多只能选择三项');                }              }           }