Validating a form on the client

When the client verifies the form, the submit button cannot be used to block the default event, and to prevent form submission, prevent the Sumint event from being committed on the form;

<!
    DOCTYPE html>  

 
/** * Created by Wenguang on 2015/12/4.
    */function Checkpassword () {//var Psw=document.getelementbyid (' PSW ');
    var Psw1=document.getelementbyid (' PSW1 ');
    var Test=document.getelementbyid (' Test2 ');
        if (psw.value!=psw1.value) {test.innerhtml= ' two times password inconsistent, please re-enter ';

return false} else return true;
    The function Checknotnull () {//Determines whether to be an empty var User=document.getelementbyid (' user ');
    var Psw=document.getelementbyid (' PSW ');
    var Psw1=document.getelementbyid (' PSW1 ');
        if (user.value== "") {var Span0=document.getelementbyid (' Test0 ');
        Span0.innerhtml= ' The item cannot be empty ';
    return false;
        else if (psw.value== "") {var Span1=document.getelementbyid (' test1 ');
        Span1.innerhtml= ' The item cannot be empty ';
    return false;
        else if (psw1.value== "") {var Span2=document.getelementbyid (' Test2 ');
        Span2.innerhtml= ' The item cannot be empty ';
    return false;
else return true;
}//Bound event function addevent (OBJ,TYPE,FN) {    if (Obj.addeventlistener) {Obj.addeventlistener (type,fn,false);
    }else if (obj.attachevent) {obj.attachevent (' on ' +type,fn); }//cross-browser block default behavior function Preventdefault (evt) {var e=evt| |
    window.event;
    if (E.preventdefault) {e.preventdefault ();
    }else{E.returnvalue=false;
    } addevent (window, ' Load ', function () {var Fm=document.getelementbyid (' register ');
        ADDEVENT (FM, ' Submit ', function (evt) {preventdefault (evt);
            if (Checknotnull ()) {if (Checkpassword ()) {//If two times the same password is submitted to Fm.submit ();
}
        }
    });

});
    addevent (window, ' Load ', function () {//Get focus is empty hint var user=document.getelementbyid (' user ');
    var Psw=document.getelementbyid (' PSW ');
    var Psw1=document.getelementbyid (' PSW1 ');
        Addevent (user, ' Focus ', function () {var Span0=document.getelementbyid (' Test0 ');
    Span0.innerhtml= ';
    }); Addevent (PSW, ' Focus ', function () {var Span1=document.getelEmentbyid (' test1 ');
    Span1.innerhtml= ';
    });
        Addevent (PSW1, ' Focus ', function () {var Span2=document.getelementbyid (' Test2 ');
    Span2.innerhtml= ';
});

 });
 

 
*{
    padding:0;
    margin:0;
}
body{
    background: #ccc;
    padding:0;
    margin:0;
    Color: #fff;
    font-family: "Microsoft ya hei Light";
}
#login {
    width:700px;
    Height:auto;
    margin:70px Auto;
    Background: #ddd;
}
#register div{
    width:700px;
    height:30px;
    Background: #030C1D;
    margin:2px 0;
    line-height:30px;;
}
. Form-div_1 input{
    width:200px;
    height:23px;
    margin-bottom:2px
}
. label_1{
    Display:inline-block;
    width:100px;
    Text-align:right
}
. Label_1 span{
    color:red;
}
#textArea {
    height:180px!important;
    line-height:200px;
}
#textArea textarea{
    display:inline;
    width:500px;
    height:160px;
    margin:10px 0;
}
#sub_reset input{
    margin-left:100px;
    width:100px;
    height:25px;
    Background: #3e3e3e;
    Color: #fff;
    font-size:20px;
}
#zhiYe {
    width:100px;
    height:23px;
}