关于表单项更新检测,后台按需更新

<script  type="text/javascript">

Array.prototype.inArray=function (value){for (var i=0;i<this.length;i++){if (this[i] == value){return true;}}return false};    

function IsFormChanged(el) {  

    var tips="";

    var arr1=new Array(); 

    var arr2=new Array();

    var isChanged=false;

    var itemVal='';

    var form = document.getElementById(el);  

    for (var i = 0; i < form.elements.length; i++) {  

        var element = form.elements[i];  

        var type = element.type;

        switch(type){

            case "text":

            case "hidden":

            case "textarea":

            case "button":

                tips += (element.value != element.defaultValue)?tips.length==0?element.name+"='"+escape(element.value)+"'":"&"+element.name+"='"+escape(element.value)+"'":"";

                break;

            case "radio":

                if(!arr1.inArray(element.name)){

                    arr1.push(element.name);

                    var myRadio=document.getElementsByName(element.name);

                    for(var k=0;k<myRadio.length;k++){

                        tips += (myRadio[k].checked && !myRadio[k].defaultChecked)?tips.length==0?myRadio[k].name+"='"+myRadio[k].value+"'":"&"+myRadio[k].name+"='"+myRadio[k].value+"'":"";

                    }

                }

                break;

            case "checkbox":

                if(!arr2.inArray(element.name)){

                    arr2.push(element.name);

                    isChanged=false;

                    var myBox=document.getElementsByName(element.name);

                    itemVal='';

                    for(var k=0;k<myBox.length;k++){

                        if(myBox[k].checked){//当前checkbox被选中

                            if(!myBox[k].defaultChecked){isChanged=true}//是否与初始状态不同,如果是则标记为当前checkbox需更新

                            itemVal += itemVal.length==0?myBox[k].value:","+myBox[k].value;//同一name追加值

                        }else{

                            if(myBox[k].defaultChecked){

                                isChanged=true;//初始化时为选中状态但当前未选中，标记该复选框组值需更新

                            }

                        }

                    }

                    if(isChanged){itemVal=element.name+"='"+itemVal+"'";tips+=tips.length==0?itemVal:'&'+itemVal}

                }

                break;

            case "select-one":

                for (var j = 0; j < element.options.length; j++) {

                    tips += (element.options[j].selected && !element.options[j].defaultSelected)?tips.length==0?element.name+"='"+element.value+"'":"&"+element.name+"='"+element.value+"'":"";  

                }

                break; 

            case "select-multiple": 

                isChanged=false;

                itemVal='';

                for (var j = 0; j < element.options.length; j++) {

                    if(element.options[j].selected){

                        if(!element.options[j].defaultSelected){isChanged=true}//是否与初始状态不同,如果是则标记为当前select需更新

                        itemVal +=itemVal.length==0?element.options[j].value:","+element.options[j].value;//同一个元素只追加值  

                    }else{

                        if(element.options[j].defaultSelected){

                            isChanged=true;//初始化时为选中状态但当前未选中，标记该select值需更新

                        }

                    }

                }

                if(isChanged){itemVal=element.name+"='"+itemVal+"'";tips+=tips.length==0?itemVal:'&'+itemVal}

                break;  

        } 

    }

    tips.length==0?alert('没有更新项'):alert(tips);

 } 

</script>

<form id="chageform" action="">

    text：<input type="text" name="txt1" value="1"/><br />

    myBox：<input type="checkbox" name="myBox" checked="checked" value="1"/>

    <input type="checkbox" name="myBox" value="2"/>

    <input type="checkbox" name="myBox" value="3"/><br />

    

    myBox2：<input type="checkbox" name="myBox2" checked="checked" value="4"/>

    <input type="checkbox" name="myBox2" checked="checked" value="5"/>

    <input type="checkbox" name="myBox2" value="6"/><br />

    

    myRadio：<input type="radio" name="myRadio" checked="checked" value="1"/>

    <input type="radio" name="myRadio" value="2"/><br />

    

    myRadio2：<input type="radio" name="myRadio2" value="1"/>

    <input type="radio" name="myRadio2" checked="checked" value="2"/><br />

    

    mySel：<select name="mySel">

    <option value="1" selected="selected">1</option>

    <option value="2">2</option>

    </select><br />

    

    mySel2：<select name="mySel2">

    <option value="1">1</option>

    <option value="2" selected="selected">2</option>

    </select><br />

    

    mySel3：<select name="mySel3" multiple="multiple" style="width:50px;">

    <option value="1">1</option>

    <option value="2" selected="selected">2</option>

    <option value="3">3</option>

    <option value="4" selected="selected">4</option>

    <option value="5">5</option>

    </select><br />

    

    mySel4：<select name="mySel4" multiple="multiple" style="width:50px;">

    <option value="1">1</option>

    <option value="2" selected="selected">2</option>

    <option value="3">3</option>

    <option value="4" selected="selected">4</option>

    </select><br />

<input type="button" value="检测" onclick="IsFormChanged('chageform')" />

</form>