


A little experience in operating the select drop-down list box with javascript_form special effects
According to my usual web development style, all events that do not directly operate the database are implemented by JavaScript as much as possible, so I plan to use js to complete this requirement.
First, let’s analyze the specific situation: This page is an update page. The brand has two fields: brand 1 and brand 2. Brand 2 can be empty, but brand 1 cannot be empty, so the drop-down list box of brand 2 is smaller than that of brand 1. One more item; if any of the first 8 images of the brand is selected, the "active status" should be hidden, otherwise the default display status of "active status" is "potential"; when the query results of brand 1 and brand 2 have any one In the first 8 photos of the brand, the "active status" must also be hidden, otherwise the default display status of "active status" is "potential".
Part of the page content
javascript code
function changebrand1(oTextbox)
{
var brandTag=document.getElementById("ddlistSecondConsumeBrand");
var brand1=document.getElementById("txtbrand1");
var brand2=document.getElementById("txtbrand2");
var brandcolls=brandTag.options;
var textvalue=oTextbox.value;
var flag=0;
if(textvalue.length==0)
{
flag=1;
}
else if(textvalue.length>0)
{
for(var i=0;i
if(oTextbox==brand1 && brandcolls[i].text==textvalue)
{
document.getElementById("ddlistFirstConsumeBrand").options.selectedIndex=i-1;
flag=1;
ChangeBrand(document.getElementById("ddlistFirstConsumeBrand"));
}
else if(oTextbox==brand2 && brandcolls[i].text==textvalue)
{
brandTag.selectedIndex=i;
flag=1;
ChangeBrand(brandTag);
}
}
if(flag==0)
{
alert("输入品牌错误!");
oTextbox.value="";
oTextbox.focus();
}
}
}
function ChangeBrand(me){
var brand1ID = document.all.ddlistFirstConsumeBrand.value;
var brand2ID = document.all.ddlistSecondConsumeBrand.value;
var brandvalue1=document.getElementById("txtbrand1");
var brandvalue2=document.getElementById("txtbrand2");
if((brand1ID=="10")&&(brand2ID=="-1"))
{
document.all.ddlistMilkPeriod.value=9;
}
for(var i=0;i
if(document.getElementById("ddlistFirstConsumeBrand") == me && document.all.ddlistFirstConsumeBrand.selectedIndex==i)
{
brandvalue1.value=document.getElementById("ddlistFirstConsumeBrand").options[i].text;
}
if(document.getElementById("ddlistSecondConsumeBrand") == me && document.all.ddlistSecondConsumeBrand.selectedIndex==i)
{
brandvalue2.value=document.getElementById("ddlistSecondConsumeBrand").options[i].text;
}
if(i<8 && document.getElementById("ddlistFirstConsumeBrand") == me && document.all.ddlistFirstConsumeBrand.selectedIndex==i)
{
document.all.dv1.style.display="block";
document.all.dv2.style.display="none";
document.all.dv3.style.display="none";
document.getElementById("ddlistPotential").options[0].selected="selected";
break;
}
else if(i>0 && i<9 && document.getElementById("ddlistSecondConsumeBrand") == me && document.all.ddlistSecondConsumeBrand.selectedIndex==i)
{
document.all.dv1.style.display="block";
document.all.dv2.style.display="none";
document.all.dv3.style.display="none";
document.getElementById("ddlistPotential").options[0].selected="selected";
break;
}
else if(i>8)
{
document.all.dv1.style.display="none";
document.all.dv2.style.display="block";
document.all.dv3.style.display="block";
document.getElementById("ddlistPotential").options[1].selected="selected";
}
}
}

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