function bnt_selall_onClick(){
var TheForm = document.form1;
for (i=0;i<TheForm.elements.lenth;i++){
TheForm.elements(i).checked=true;
}
}
var TheForm = document.form1;
for (i=0;i<TheForm.elements.lenth;i++){
TheForm.elements(i).checked=true;
}
}
var TheForm,i,value
TheForm = document.form1
for (i=0;i<TheForm.length;i++)
TheForm[i].checked='true'
}
<a href="javascript:bnt_selall_onClick();">全选</a>
或者直接在js中需要调用的地方加上 bnt_selall_onClick();