The code has several unescaped quotes. I believe it should look like this:
<script LANGUAGE=javascript>
<!--
document.write("function trim(strField)" + "<br>");
document.write("{" + "<br>");
document.write(" for(loop=0,space=0;strField.substr(loop,1)==\" \" &&loop < strField.length;loop++,space++);" + "<br>");
document.write(" strField=strField.substr(space,(strField.length-space));" + "<br>");
document.write(" for(loop=strField.length,space=0;strField.substr(loop-1,1)==\" \" && loop>0;loop--,space++);" + "<br>");
document.write(" strField=strField.substr(0,strField.length-space);" + "<br>");
document.write(" return strField;" + "<br>");
document.write("}" + "<br>");
document.write("function validateForm()" + "<br>");
document.write("{" + "<br>");
for(var i=0;i<document.forms[0].elements.length;i++)
{
if(document.forms[0].elements[i].type=="text" |document.forms[0].elements[i].type=="textarea")
{
document.write("document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".value=trim(document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".value);<br>");
}
}
for(var i=0;i<document.forms[0].elements.length;i++)
{
if(document.forms[0].elements[i].type=="select-one")
{
document.write("if(document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".selectedIndex==0)<br>");
document.write("{<br>");
document.write(" alert(\"Please select a value\");<br>");
document.write(" document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".focus();<br>");
document.write(" return false;<br>");
document.write("}<br>");
}
if(document.forms[0].elements[i].type=="text")
{
document.write("if(document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".value==\"\")<br>");
document.write("{<br>");
document.write(" alert(\"Please enter a value\");<br>");
document.write(" document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".focus();<br>");
document.write(" return false;<br>");
document.write("}<br>");
}
if(document.forms[0].elements[i].type=="password")
{
document.write("if(document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".value==\"\")<br>");
document.write("{<br>");
document.write(" alert(\"Please enter a value\");<br>");
document.write(" document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".focus();<br>");
document.write(" return false;<br>");
document.write("}<br>");
}
if(document.forms[0].elements[i].type=="checkbox")
{
document.write("if(document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".checked==false)<br>");
document.write("{<br>");
document.write(" alert(\"Please check a value\");<br>");
document.write(" document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".focus();<br>");
document.write(" return false;<br>");
document.write("}<br>");
}
if(document.forms[0].elements[i].type=="radio")
{
document.write("if(document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".status==false)<br>");
document.write("{<br>");
document.write(" alert(\"Please check a value\");<br>");
document.write(" document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".focus();<br>");
document.write(" return false;<br>");
document.write("}<br>");
}
if(document.forms[0].elements[i].type=="textarea")
{
document.write("if(document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".value==\"\")<br>");
document.write("{<br>");
document.write(" alert(\"Please enter a value\");<br>");
document.write(" document."+document.forms[0].name+"."+document.forms[0].elements[i].name+".focus();<br>");
document.write(" return false;<br>");
document.write("}<br>");
}
}
document.write("return true;" + "<br>");
document.write("}" + "<br>");
//-->
</SCRIPT>