javascript——表单校验工具代码

    function changeImg(img){
        //改变img标签中 src的值，实现重新加载的功能  每次的访问地址都不一样，因为有变量加入，所以每次都会访问新的资源。
        img.src = img.src+"?time="+new Date().getTime();
     }
//检查username输入框
    function checkUsrname(){
        var canSub = true;
        var username_v = this.value;
        if(checkNull("username","用户名不能为空！")==null){
            return ;
        }else{

        }
    }
    function checkPhonenum(label_phonenum){
        var phonenum_v = label_phonenum.value;
        if(checkNull("phonenum","手机号码不能为空！")==null){
            return ;
        }else{
            if(phonenum_v.length!=11){
                document.getElementById("phonenum_msg").innerHTML = "<font color='red'> 请输入11 位手机号码！</font>";
            }
        }
        return ;
    }
    function checkPsw(label_psw){
        var username_v = this.value;
        if(checkNull("password","密码不能为空！")==null){
            return ;
        }else{

        }
    }
    function checkPsw2(label_psw2){
        var psw2 = label_psw2.value;
        var psw1 = document.getElementsByName("password")[0].value;
        if(checkNull("password2","确认密码不能为空！")==null){
            return ;
        }else{
            if(psw1!=psw2 && psw1!=null){
                document.getElementById("password2_msg").innerHTML = "<font color='red'>两次密码不一致！</font>";
            }
        }
    }
    function checkEmail(label_email){
        var email_v = label_email.value;
        checkNull("email","邮箱不能为空！");
        if(email_v!=null && email_v!="" && !/^\w+@\w+(\.\w+)+$/.test(email_v)){
            document.getElementById("email_msg").innerHTML = "<font color='red'>邮箱格式不正确！</font>";
//          canSub = false;
            return ;
        } 
    }
    function checkValiImg(label_valiStr){
        var valiStr = label_valiStr.value;
        checkNull("valistr","验证码不能为空！");
        return ;
    }
//  //前端页面格式校验
//  function checkForm(){
//      //1.非空校验
//      var canSub = true;
//      canSub = checkNull("username","用户名不能为空！") && canSub;
//      canSub = checkNull("password","密码不能为空！") && canSub;
//      canSub = checkNull("password2","确认密码不能为空") && canSub;
//      canSub = checkNull("phonenum","手机号码不能为空！") && canSub;
//      canSub = checkNull("email","邮箱不能为空！") && canSub;
//      canSub = checkNull("valiStr","验证码不能为空！") && canSub;
//      //2.两次密码一致校验
//      var psw1 = document.getElementsByName("password")[0].value;
//      var psw2 = document.getElementsByName("password2")[0].value;
//      if(psw1 != psw2){
//          document.getElementById("password2_msg").innerHTML = "<font color='red'>两次密码不一致!</font>";
//          canSub = false;
//      }
//  //3.邮箱格式校验
//  var email = document.getElementsByName("email")[0].value;
//  if(email!=null && email!="" && !/^\w+@\w+(\.\w+)+$/.test(email)){
//      document.getElementById("email_msg").innerHTML = "<font color='red'>邮箱格式不正确！</font>";
//      canSub = false;
//  }       
//          
//      return canSub;
//      
//  }

    function checkNull(name,msg){
        document.getElementById(name+"_msg").innerHTML = "";
        var objValue = document.getElementsByName(name)[0].value;
        if(objValue==null || objValue==""){
        document.getElementById(name+"_msg").innerHTML = "<font color='red'>"+msg+"</font>";
            return false;
        }
        return true;
    }