js基础

屏幕快照 2017-09-12 上午10.55.40.png

script追加新元素

window.onload = function(){ //init()
                document.getElementById("addCitySender").onclick = function(){ //button的onclick匿名函数
//                 alert("123");
                    var newCityWord = document.createTextNode("深圳"); //创建一个只有文字的节点
                    var newEle = document.createElement("li");    //创建一个元素 <li></li>
                    newEle.appendChild(newCityWord);   //元素中加入节点<li>深圳</li>
                    var list = document.getElementById("ul_list"); //获取list
                    list.appendChild(newEle); //追加到现有的list中
                }
            }

script全选全不选

    function selectOrUnselectAllAction(){
                var isChcked = document.getElementById("selectOrUnselectAll").checked;
                var eles = document.getElementsByName("checkOnebox");
                for (var i = 0; i < eles.length; i++) {
                    if(eles[i].checked != isChcked){
                        eles[i].checked = isChcked;
                    }
                }
            }

script获取table中的row元素 并设置style

window.onload = function () {
                
                document.getElementById("table").tHead.style.backgroundColor = "gray";
                
                var tableRows = document.getElementById("table").tBodies[0].rows;
                for (var i = 0; i < tableRows.length; i++) {
                        if(i % 2 == 0){
                                tableRows[i].style.backgroundColor = "pink";
                        }else{
                               tableRows[i].style.backgroundColor = "yellow";
                        }
                    }
            }

省市选择 onchange / object.options.length = 0;

//html

<td>  //select标签值改变的事件  onchange 传入当前选择的值 -- this.value
    <select id="province" onchange="changeprovinceAction(this.value)"> 
         <option>---请选择----</option>
        <option value="0">安徽</option>
         <option value="1">江苏</option>
         <option value="2">浙江</option>
     </select>
                      
    <select id="city">
     </select>

//script

 var citys = new Array();
 citys[0] = ["亳州","合肥","芜湖","安庆"];
citys[1] = ["南京","苏州","无锡","常州"];
citys[2] = ["杭州","慈溪","金华","义务"];
            
    function changeprovinceAction(prove){
        var cityEle = document.getElementById("city");
        cityEle.options.length = 0; //将上一个省份的城市置空
        for (var i=0;i<citys.length;i++) {
            if(i==prove){
                for (var j = 0; j<citys[i].length;j++) {
                     var city = document.createTextNode(citys[i][j]);
                      var ele = document.createElement("option");
                    ele.appendChild(city);
                    cityEle.appendChild(ele);
                }
                    break;
                 }
        }
    }

开始编辑 结束编辑 onfocus / onblur / innerHTML

            function onfocusAction(eleId,specificId){
            
                var spanTips = document.getElementById(eleId + "Tips");
                var tipsStr;
                switch(specificId){
                    case 0: {   
                        tipsStr = '用户名必填!'; break;
                  }
                 case 1: {
                       tipsStr = '密码必填!';break;
                  }
                }
                spanTips.innerHTML = ('<font color="gray">'+tipsStr+'</font>');             
            }
            
            function onblurAction(eleId,specificId){
                
                var targetEle = document.getElementById(eleId);
                var spanTips = document.getElementById(eleId + "Tips");
                var tipsStr;
                switch(specificId){
                    case 0: {   
                         if (targetEle.value ==""){
                            tipsStr = '用户名不能为空!'; 
                         }else if(targetEle.value.length > 10){
                            tipsStr = '用户名不能超过10个字!'; 
                         }else{
                             tipsStr = ''; 
                         }
                       break;
                  }
                 case 1: {
                    if (targetEle.value ==""){
                        tipsStr = '密码必填!';
                    }else{
                         tipsStr = ''; 
                    }   
                       break;
                  }     
            }
                spanTips.innerHTML = ('<font color="red">'+tipsStr+'</font>');      
        }