Seek the code about the drop-down box! !

Let me give you an example. Change the data yourself.

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& lthtml & gt

& lthead & gt

& lt/head & gt；

& ltbody & gt

& lt scripting language = "JavaScript">

& lt！ -

//First Dimension: the value of the first drop-down list.

//Second dimension: indicates the string seen in the drop-down list.

//The third dimension: indicates the value in the drop-down list.

var subcat = new Array()；

//If the value of the category is dynamic, it can be retrieved from the database and set as follows.

//subcat[& lt； % = count%>] = new array ('<% = trim(RS(" leemaid ")%>；)%>' ，' & lt% = RS(" leemacontent nt ")% & gt；' ，' & lt% = RS(" leemacontent ")% & gt；' );

Subcat[0] = new array ('1',' TV',' = 1')

Subcat [1] = new array ('1',' electric fan',' =2')

Subcat[2] = new array ('1',' rice cooker',' =3')

Subcat[3] = new array ('1',' electric cooker',' =4')

Subcat[4] = new array ('1',' electric light',' =5')

Subcat[5] = new array ('1',' computer',' =6')

Subcat[6] = new array ('1',' refrigerator',' =7')

Subcat[7] = new array ('1',' washing machine',' =8')

Subcat[8] = new array ('1',' microwave oven',' =9')

Subcat [9] = newarray (' 1 '，' VCD player '，' = 1 ')

Subcat[ 10] = new array ('2',' diode',' =1')

Subcat [1 1] = new array ('2',' triode',' = 12')

Subcat [12] = newarray ('2',' CMOS integrated module',' = 13')

Subcat[ 13] = new array ('2',' resistance',' = 14')

Subcat[ 14] = new array ('2',' capacitance',' = 15')

Subcat[ 15] = new array ('2',' rectifier diode',' = 16')

Subcat[ 16] = new array ('2',' rectifier bridge',' = 17')

Subcat[ 17] = new array ('2',' SCR',' = 18')

Subcat[ 18] = new array ('2',' electron gun',' = 19')

Subcat[ 19] = new array ('2',' photodiode',' =2')

Subcat[20] = new array ('3',' ffffff',' vvvvvv')

Subcat[2 1] = new array ('3',' dddddd',' ffffff')

Function change selection 1 (selection value)

{

document . form 1 . S2 . length = 0； //Initialize the drop-down list and empty the drop-down data.

//document.form1.s2.options [0] = newoption ('Please select a secondary subclass',''); //Give the first value

for(I = 0； I & ltsubcat.lengthi++)//legth=2

{

If (subcat [I] [0] = = selected value)/[0] [1] first column and second column.

{

document . form 1 . S2 . options[document . form 1 . S2 . length]= new Option(subcat[I][ 1]，subcat[I][2])；

}

}

}

//-& gt；

& lt/script & gt；

& ltform name="form 1 " >

Secondary link:

& ltselect name = " s 1 " onChange = " changeselect 1(this . value)" & gt；

& lt Options & gt Please select a first-level category.

& ltoption value=" 1 "> household appliances

< option value = "2" > electronic components

& ltoption value="3 " >ddddd & lt/option & gt；

& lt/select & gt；

& ltselect name = " S2 " onChange = " alert(this . value)" & gt；

& lt Options & gt Please select a secondary subcategory.

& lt/select & gt；

& lt/form & gt；

& lt/html & gt；